Have the following on hand:
- Canned black beans
- Bag of pre-shredded taco mix cheese
- Jar of fresh-tasting salsa
Other options to throw in: bag of salad mix, plain yogurt, avocado slices, tortillas, etc.
There are many ways to assemble this. You don't necessarily have to use tortillas or taco shells. Sometimes I just huck everything into a big bowl; other times I carefully microwave or broil the cheese over the rice and beans.
To cook the beans when I want something fast, I just heat them. That's it. Heat. Them.
Another thing I like about this is the lack of pre-planning required. You can have the salsa, beans, and rice on hand in the pantry and freeze the pack o' cheese. You can then use the next day or the next month.
It's tasty, filling, and terribly, terribly fast.