Place about 1 Tbsp oil into a skillet and turn up the heat. Once the oil is hot, add 1 corn tortilla at a time. Flip when it bubbles and the edges turn brown. Set aside to cool. Repeat with the remaining tortillas.
Blend up the spicy beans. (3 cans pinto beans well drained, 1 can Rotel diced tomatoes with green chilies, 1 tsp ground cumin and 3 garlic cloves. Stream in a little olive oil if you need to.)
Once the tostadas have cooled slightly and have hardened, add some spicy beans on top. Top with diced avocado, diced tomatoes, and shredded cheese.
If you want melted cheese, microwave for 45 seconds - 1 minute.
Other topping options...taco meat, shredded chicken, beans, shrimp...lettuce, tomatoes, corn, peppers, salsa roja, salsa verde, fresh cilantro, sour cream, cheese!