Slit open the chorizo package and fry over medium heat until the sausage is cooked – about 5 minutes – breaking it up as it cooks. Remove from the heat and use a slotted spoon to remove the sausage from the pan; drain out as much of the fat as possible. Discard excess fat. Place the refried beans, including the juice, in the frying pan. Stir and heat until the beans soften. Add the chorizo and mix together. You will spread this mixture on your tostada. I do not add seasonings to this particular mixture but rather rely on the additional toppings for flavor.
The third step is to prepare your additional toppings. I like to prepare a selection of toppings and set them out as a “tostada bar” so guests can build a tostada according to their own personal taste. Toppings can include: crema or sour cream, thinly sliced lettuce, chopped spinach, chopped and seeded tomato, chopped onion or sliced table onions, ripe olives, sliced or diced avocado, chopped and seeded bell peppers, shredded cheese (cheddar, Mexican blend, Mexican melting cheese, or crumbled queso fresco). Use anything you like!
To serve, spread or spoon a layer of your main ingredient on the tostada, add additional topping, and serve.