To make homemade tostada shells in oven: Preheat oven to 400 degrees. Brush both sides of tortillas with olive oil. Sprinkle with salt and a dusting of chile powder. Arrange in a single layer on a baking sheet. Bake for 3 minutes, flip, add more salt and chile powder and bake for additional 3-5 minutes. Or until the shells are crispy. Once tortillas are done baking, begin to assemble tostadas. Oven baked tostada shells are best served right out of the oven, so while tortillas are baking make sure all toppings are ready to go.
How to make tostada shells stovetop: Heat 1 cup vegetable oil in an 8 inch skillet over high heat until it bubbles vigorously when the edge of the corn tortilla touches it's surface.Fry 1 tortilla at a time, turning once using tongs. Fry until it's crispy, puffed in places and deeply golden brown, about 1 minute per side. Transfer the tostada to to a sheet pan lined with paper towels. Repeat wit the remaining tortillas.A cup of oil will make about 8 tostada shells.
In a fry pan, cook the chorizo until nice and crispy and cooked through.
For The Beans: Place beans in a microwave safe dish. Gently heat. Set aside and keep warm.
Grate the cheese and set aside.
Build that Tostada: Spread each tortilla with 2 - 3 tablespoons of refried beans. Top each tostada with about ¼ cup of grated cheese. Carefully add the cooked chorizo to the top of the cheese.
Bake the tostadas in the 400 degree oven until the cheese is nice and melted. All oven vary, but this should take less than 5 minutes.
Toppings: Smashed avocado or guacamole. Rings of fresh jalapeno pepper, or pickled jalapeno slices. A dollop of sour cream, or crumbled cotija cheese.