Ethan, I've never eaten hot peppers or salsa on a regular basis because I kind of save the effect for an emergency (like when I'm really having trouble swallowing or breathing). The reason I got worse from the cottage cheese was because of the potassium sorbate added to it. Plain cottage cheese with no additives is fine for me.
When my youngest daughter was little she would get myotonia in her eye muscles from eating eggs for some reason and on her own she learned to use Tabasco sauce every time she ate eggs to avoid the reaction.
My favorite is Pace brand sliced jalapenos...they don't have coloring or sulfites added and work quickly even if I just drink a teaspoon or so of the juice.
It would be really hard to work around school lunches. You can probably pick and choose to avoid much sugar, but it would be hard to know which foods have potassium additives without reading the labels.
If your district has a dietician that plans the menus then she should be able to give you a list of foods from the menu that would fit the criteria. You might ask the kitchen staff how to get in touch with her or call your district's administrative office. You're welcome to give her my contact information and I can explain what we have to watch for.
I just wanted to insert my 2 cents, because it seems that there is an alternative to school lunches... make and bring your own. When my son was in school, we made his lunch every single day, from 1st grade all the way through high school... we did it because of the awful quality of school food - cheap, over-prepared, treated foods with so little nutritional value left after being over-cooked... Josh's favorite thing was Roman Meal bread with turkey breast and alfalfa sprouts, a Juicy Juice box (100% juice, no sugar, colers, etc...), some "baby" carrots in a baggie, and some fruit for dessert (and occasionally a handful of pretzels)... he was happy, and so were we! You could make your own lunches, and be master of your own destiny! Lois (lolonurse)