Black bean tostadas are quick and easy to make, and they'll easily feed a small crowd without breaking the bank. Stuff warm tostadas with mashed black beans, lettuce, tomatoes, onions and any other toppings that you want to include. You can add sour cream, chopped avocados or even jalapeño peppers. Ingredient combinations for tostadas are limitless, and recipes can be revised to make a great meal that can be served for breakfast, lunch or dinner. One thing's for certain, though: The black beans are mandatory!