Preheat the oven to 425°F. In a small skillet, heat 1/2 inch of oil over medium-high heat until very hot. A small bit of tortilla will sizzle when the oil is ready.
Fry the tortillas until stiff. Place the tortillas on a rimmed baking sheet and bake until brown and crunchy, 5 to 7 minutes.
If using tostada shells
Preheat the oven to package directions. Lay the tostada shells out on a baking sheet.
Warm the shells in the oven, according to package instructions.
Once you have the shells ready,
Warm the refried beans in a saucepan until bubbly.
Spread the beans over the crisp tortilla shells. Top with the cheese, lettuce, tomatoes, sour cream, and other toppings.
*For quickest assembly, use tortilla shells already fried at the grocery store. Promptly store leftovers in an airtight container in the refrigerator, for up to 3 days for ingredients, up to 8 hours for assembled tostada.Nutritional values are approximate and based on 1 tostada.