Place Anaheim green chilies, tomatoes, onion, and garlic cloves in a bowl. Toss with olive oil until evenly coated. Place vegetables on a rimmed baking sheet. Bake 10 minutes and remove garlic cloves; set aside for use in step 3. Continue baking chilies, tomatoes, and onion until roasted and browned, about 35 more minutes.
Peel and seed chilies. Remove outer skin from tomatoes. Add all roasted ingredients to food processor; pulse to a chunky consistency. Let mixture cool.
Mash avocados with a fork in a large bowl to a chunky consistency. Add lemon juice, roasted salsa mixture, seasoned salt, cayenne pepper, dash of coarse black pepper, and chopped cilantro. Stir until blended and serve.