Bake the taco shells for amount of time recommended on the package. Cook the beans on medium and let them simmer with your favorite seasonings, stir occasionally. Grate the cheese into a bowl. Dice the tomatoes and put them in a bowl. Rinse the lettuce and put it on a plate (don't cut or shred the lettuce). Take a taco and either put the beans in, then the cheese, then the sauce, then the tomato, and then a big leaf of lettuce to top it all off; or put the lettuce on the bottom of it all to keep the she'll from getting soggy.