Tostadas are an excellent appetizer or a complete meal. These Paleo, vegan tostadas can be made really simply with store bought and Paleo compliant guacamole and diablo sauce – many brands are gluten-free. If you are feeling adventurous, make the guacamole and sauce from scratch, as outlined here.
Diablo Sauce: In a medium saucepot, add the dried chiles and cover with boiling water. Place a lid on the pot and allow the chiles to sit for 15 minutes. Using a slotted spoon, transfer the softened chiles to a blender. Add the tomatoes, garlic, onion, salt, and oregano and purée until smooth. Place the sauce in a small serving bowl and set aside.
Guacamole: Place the flesh from the avocado halves in a large bowl and mash them with a fork. Mix in the lime juice, tomatoes, onion, and cilantro. Season with salt and pepper. Placed the pits in the guacamole to prevent it from turning brown until ready to use. Cover and place in the refrigerator.
Fillings and Tostadas: In a medium bowl, combine the cabbage, carrots, lime juice, 1 tablespoon of the olive oil, and 1/2 teaspoon salt. Toss and set aside. In a large skillet over medium-high heat, warm 2 to 3 tablespoons of oil. Add the garlic, bell pepper, and mushrooms. Sauté until just cooked through, approximately 6 to 7 minutes. Season with the salt and pepper. Place the mixture in a bowl and wipe the pan down with a paper towel and place back on the heat.
Assembly: Warm the tortillas in the sauté pan and remove them to 1 or 2 large serving platters. You will have to do this in batches. Top each tortilla with a spoonful of mushroom mixture, then some slaw, and finally the guacamole. Serve the diablo sauce on the side with a spoon. Place lime wedges on the platters and serve with plenty of napkins.