Are there any seeds that will tolerate growing in decomposing scraps of food? My city collects organic waste, but I thought I'd try to put it to use myself. I have a can of sweetened red bean paste that's growing aggressive fuzzy gray mold and there is a population of fruit flies trapped inside under the cling wrap. Currently, I put the can on my windowsill for observation. Is there a possibility to grow any plant in there? I'm worried about the seeds germinating but then the mold chokes out the seedling.
Usually it is much better to produce compost, and use compost as amendment of soil for your vegetable garden.
The problem of decomposing stuffs is the heat: decomposition will create a lot of heat (you may see on lower layers some ash). In addition fruit flies and very different composition over time will make growing stuff difficult.
When it is "ripe", you can growth nearly everything. I do not recommend to use it before.
Note: some mushrooms are growth on decomposing stuff (and mushrooms are actively decomposing stuffs).
Short answer: none unless your decomposing scraps are let in a pile on the ground for several months.
If you live in a cold area, put a few buckets of scraps on the ground before the coldest time of the year, and when the weather warms up again you should see plants popping up. Classic hardy seeds that do this are tomatoes, squash, melons, cucumbers.
You definitely will not get good results by trying to grow plants in a can of processed food.
To grow from seed in food scrap, you need to compost the scrap properly beforehand. When your scraps are ready to be used for growing, it will be multi-textured (think vegetable salad chopped in small bits), on the dry side so as to prevent rot (which will not allow germination of most seeeds) and of a relatively uniform color.
Even then, any volume of compost from food scrap needs to be mixed with about a third of sand/soil/pebbles, etc if you want a healthy plant.