1. To make the baked tostada shells, preheat the oven to 400 degrees F. Spray each side of the corn tortillas with cooking spray. Season with salt. Place tortillas on a large baking sheet and bake until tostadas are lightly browned and crisp on one side, about 3-5 minutes. Remove from oven and flip the tortillas. Place back in the oven and cook until lightly browned and crisp on the other side, about 3-5 minutes. Set aside.
2. Pour olive oil into a large heavy bottom skillet and place over medium high heat. Add onion and cook until tender, about 5 minutes. Stir in the garlic and cook for 2 more minutes. Stir in the red pepper and cook until tender, about 3-4 minutes.
3. Add tofu and season with chili powder, cumin, and salt and pepper, to taste. Squeeze fresh lime juice over the tofu and cook until tofu is brown on each side, about 5 minutes. Stir in the fresh cilantro.
4. Place tofu mixture on top of a crisp tostada shell. Garnish with tomatoes, avocado, cilantro, lime juice-if desired.
Note-Feel free to add your favorite toppings to the tostadas. Cheese, black beans, salsa, sour cream, and hot sauce are also great!