Turn oven broiler setting on. Place jalapeños on a baking sheet six inches from the broiler. Broil 5 - 6 minutes on each side or until they begin to blacken. Remove jalapeños from oven and allow to cool.

Once cool, remove and discard stems. Place jalapeños, garlic, cilantro, onions, vinegar, cumin and salt in a food processor. Process until minced fine. It will still be a little chunky. Cover and refrigerate until ready to use.

Heat 1 tablespoon avocado oil in a skillet over medium heat. Add in chicken, onion, chili powder and cumin. Cook until chicken is warmed through and onions have softened. Season to taste with salt. Remove from skillet and cover with aluminum foil to keep warm while you fry the tortillas.

Heat a thin layer of avocado oil in skillet. Once hot, cook tortillas one at a time, 30 seconds on each side or until browned and crispy. Transfer to a paper towel lined plate.

To assemble tostadas: Place a tortilla on a plate. Scoop chicken on top. Top with lettuce, cheese, guacamole and sour cream. Drizzle roasted jalapeño salsa over the top. Serve.