Heat the olive oil in a medium skillet over medium-high heat. Add the beans and the liquid. Cook over medium heat, mashing the beans with a potato masher, stir until they form a thick paste, about 10 minutes. Season to taste with salt and pepper.
Tortilla Frying Directions:
In heavy skillet heat one-quarter inch oil. Fry tortillas, one at a time, in hot oil for 20 to 40 seconds on each side or until crisp and golden. Drain on paper towels. Store bought tostadas can also be used.
Top one tostada with guacamole and one with refried beans. Garnish each with lettuce (optional), tomato and, cheese. Drizzle with your favorite homemade salsa to taste.
Now that you have tried this classic combo, you can come up with all sorts of different ways to top them off.