Here are some solutions I've found:
Crockpots Are Your Friend
Cooking dry beans. Lately I've mostly been making black beans, but here's where I wrote about making pinto beans in the crockpot. When I do black beans I don't add any seasonings while cooking, but otherwise it's the same idea.
Once the beans are cooked, we usually have one meal of beans and rice. I stir salsa into some of the beans to season them, then cook rice (if you have a rice cooker, that would be even less heat in the kitchen!) and serve it plain, or stir salsa into it to make "Spanish rice".
Another recipe that I use the beans for is Taco Soup. While I don't normally think of soup as an ideal summer food, the crockpot makes it lower heat than most lunch options :)
Last week I shared about making tomato soup from fresh tomatoes in the crockpot. A great way to use that garden goodness without heating up the kitchen.
Another crockpot idea I just saw and can't wait to try, is baked potatoes in the crockpot!
Tomato Basil Salad: This really doesn't need a recipe, just chop up tomatoes, and a block of fresh mozzarella, add a handful of fresh basil, salt to taste (and a little lemon juice if the tomatoes aren't juicy enough), stir it up, and dig in.
Black Bean Salsa: This salad uses some more of those black beans I cooked in the crockpot. I haven't gotten around to posting my recipe, but this one is similar. Served with chips, it makes a yummy, easy lunch, no cooking involved (I use canned corn w/o cooking it at all)
Pasta salad - the down side is, you have to cook the pasta. What I try to do is cook a big batch of pasta for supper one night, and serve it with red sauce or butter and cheese, and then use the leftover for pasta salad for lunch the next day.
Yogurt and fruit
Chocolate Kefir Milkshake
Mock Orange Julius
Orange Cream Kefir Popsicles
and once in awhile, we might have Chocolate Coconut Ice Cream for breakfast
And those a few ways that we avoid heating up the kitchen.
Visit the Schoolhouse Review Crew to see how other members of the crew avoid heating up the kitchen.