The Food Riots
The availability of food within the base setting (habitat, city, arco, etc) is severely limited, creating social unrest, a thriving black market for food, and opportunities for violence and revenge as law enforcement is being tied up controlling riots.
Large Riot - several hundred to several thousand civilians have congregated in a specific area, protesting the food shortages, demanding the local powers that be to do something about it, and generally give voice to their hunger and frustration. There will be a local force presence, under the context of preventing harm and violence, but they are present for riot control and garrison duty, protecting the wealthy and the important, as well as keeping the appearance of control over the situation. Violence is street level, large numbers of unarmed people, improvised weaponry, and when the hooligans turn up, there can be concealed hold out weapons, molotov cocktails, improvised bombs, and the basic hurled pieces of debris, sports equipment, and such.
Small Riot - a civilian organized targeted riot, this is focused on a specific objective, protesting outside of a food depot demanding they dispense food, or a police station, demanding justice for police brutality, and so forth. The large riot presents the danger of large numbers of people who are not really an enemy force, but are still motivated to hostility. The Small Riot is a mob based objective raid, and much more likely to result in mass fatalities, depending on if security forces turn on the mob with their weapons or not.
Gang Violence - organized criminal elements in the vicinity have opted to take advantage of the situation. They are running black market food sales, extortion rackets on people who have access to food, and are using the cover of the riots to further their criminal enterprises, ingratiate themselves with power players, and increase their social status.
Local Strikes - with the lack of food, many organizations, such as civilian law enforcement, entertainment personnel, business operators, and such, can be staging strikes, shutting down their specific industry as a protest over the food shortages, which can make them targets of small riots, subject to being taken over by local administration aka nationalization on a local scale.
The ultimate cause of the Food Shortage is largely irrelevant, so multiple option are provided. Most solutions are going to involve infiltrating and confronting the organization behind the shortage, overcoming it, and then dispensing food, on a short time table. It is only a matter of days before the situation stops being people being cranky and hungry and turning into a Stalingrad-esque survival situation.
Despite being almost completely self sufficient, the greatest weakness of any of the CE megastructures is the limited ability of food stores. There is a finite amount of perishable goods that can be stored, and most citizens have only a few days worth of food on hand, and a food shortage that lasts longer than 2-3 days runs the risk of becoming dangerous health wise.
Cause 1 - Corporate Embargo
Most food in the CE is industrially produced, packaged, and delivered to the end customer in a door delivery food box manner, and grocery stores are largely a thing of the past. There is a dispute between the admin of the setting and the corp that provides the food for it. There is a major dispute between the admin and the corp, and because of this, the shipments of food have stopped. The PCs have to find out if the corps are demanding outrageous price increases, if the local admin has frittered away/embezzeled all of the admin funds, or whatever local politicians vs local business shenanigans the DM decides to wrangle up.
Cause 2 - Contamination
There is plenty of food stock and rations, but the problem is that they have been contaminated, and are not safe for consumption. This can be as mundane as e. coli or salmonella contamination, heavy metal poisoning, or as exotic as having been exposed to strange radiation and going 'Colour of of Space' on the people who eat it, causing them to become insane, emaciated, and all but consumed by an alien will other than their own. The PCs have to discover this, and find out why this contamination is being covered up (local admin embarrassment, corporate value interests, gross negligence, etc) and then expose that reason, so that the bad food is disposed of and outside help is gained.
Cause 3 - Terrorism
The local food supply is gone, it has been destroyed by an act of terrorism that is not widely known. The local admin are covering the event up, and blaming the shortage of food on a convenient scapegoat until they can remedy it. The PCs are brought it to hunt down the terrorists, recover what stolen supplies they can, and stop it from happening again. Unless, unless the terrorists are in the right, and the only way to get the local populace to become away of Agenda X is to literally take the food from their mouths so that they have to look at whatever Agenda X is (local freedom, alternative community violence, local discrimination, poisoning the poor, etc). The PCs have to take up the banner of Agenda X and fight the good fight.
Cause 4 - Tyranny
The local admin is a tyranny, and the food shortage is just another tool they use to justify high taxes, large and amply armed law enforcement, routine violations of human rights, and so forth. There is plenty of food, and the Fight The Man plan is straight forward.
Cause 5 - Hoarding
There are outside worries, a looming war, a potential economic crisis, a threat to the security and integrity of the location. To that end, the more powerful and influential have started aggressively hoarding food, water, and medical supplies, as well as hiring the muscle to protect it. The shortage is entirely artificial and driven by the upper income bracket hoarding out of fear.
The Peacekeepers - tasked with keeping peace and order, the peacekeeper faction is local law enforcement, private security forces, and others who are moderately armed. They will generally side with the local admin/powers that be.
The Underground - the organized criminal element, looking to turn a profit. They sell distraction and extortion priced food, looking out for themselves first.
The Hungry Masses - just normal people who have been cut to emergency rations, and are filled with indignation over not having their snacks, their booze, and such.
The Food Providers - The people who provide, dispense, and otherwise vouch for the food supply.
The Activists - tied directly to the hostilities and oppression factor, activists are armed, innovative and motivated. They are the Something Has To Be Done, and We Gonna Do It faction.
Freelancers and Shadowrunners - elite professionals, this likely represents the PCs, and they are generally going to be hired to work for one of the factions, or be otherwise motivated to join one by sharing a common set of values and goals.
Flow of Gameplay
1. Inciting Event - PCs are drawn into a food riot, or are hired to control/disperse one (entrance is the common public area, guardian is the riot itself)
2. Puzzle/RP - the PCs are drawn in to find out what the cause of the food shortage is, and will meet at least two of the major players, one should give the cover story, one should give a closer account of the real situation)
3. Trick/Setback - the PCs discover the full truth, are forced to overplay their hands, forced to change sides, and otherwise have their story arc dramatically changed.
4. Climax/Confrontation - the PCs confront the perpetrators of the shortage, and force them to surrender. This can be a dramatic pitched fight in a geofront, hijacking a food cargo ship, supporting a local revolt, and so forth. Either way, there should be plenty of action and time for the PCs to shine in their assigned roles.
5. Reward/Plot Twist - the food shortage is ended, the PCs are heroes, and have likely made some enemies. It is also easy for the Food Shortage to dovetail into a greater problem.
Author's Note: Food shortages and riots are a common enough trope in dystopian film and fiction. This is a set-up for entry and low level characters to play in a dystopian setting on a local scale that doesn't involve alien gods, warships, the manifest destiny of humanity, and the other grandiose things that pop up in the genre. it provides ample space for colorful characters, a chance for shadowy organizations to show a bit of ankle, and for the weird stuff to show up, but the volume knob turned down low.