Heat oven to 425°F. Spray 15x10x1-inch baking pan with nonstick cooking spray. Dry corn on paper towels; spread corn in sprayed pan. Bake at 425°F. for 15 minutes. Stir; bake an additional 10 minutes. Cool 5 minutes or until slightly cooled.
In ungreased 13x9-inch (3-quart) glass baking dish, layer lettuce, bell pepper, roasted corn, onions, tomatoes and avocado.
In small bowl, combine mayonnaise and salsa; mix well. Spread over vegetables. Sprinkle with cheese and cilantro. Cover tightly; refrigerate at least 2 hours or overnight.