Heat 1 tsp. olive oil over low heat. Sauté ¼ of the scallions, peppers and mushrooms.
In a bowl, beat 3 eggs for each omelette with a whisk. Add ¼ of the salt.
Increase heat to medium. Add beaten eggs to sautéed mixture. Quickly tilt skillet in all directions so that batter will fill bottom.
Cook over medium heat approximately 2 minutes or until firm. Carefully fold omelette in half. Cook each side 1 more minute or until it is golden. Top with green chile sauce. Repeat for other omelettes.
Place the other tortilla on top. Bake at 350° for 10 minutes or until cheese melts and tortilla is golden. Or make in a cast iron skillet on top of stove, turning once, so each side of the tortillas is nicely toasted.
Preheat oven to 350º. Place corn tortillas flat on a cookie sheet. Bake at 350º for 10 minutes or until crispy. (Note: As an alternative, deep fry each corn tortilla until crispy. Drain on paper towel.)
Heat vegetable oil in large non-stick skillet.
Add and cook beans and 1 ½ cups green chile sauce over medium-high heat for approximately 20 minutes or until excess moisture evaporates.
Stir in salt and garlic. Continue cooking for 5 minutes, mashing beans.
Spoon bean mixture onto each tostada shell.
Top with remaining heated green chile sauce, tomato and cheese.