Stir together black pepper and chipotle pepper. Lightly coat burgers on both sides with cooking spray. Rub pepper mixture on both sides of burgers. Grill over medium heat for 10 to 15 minutes or until burgers reach a minimum internal temperature of 165°F, turning once. Add cheese slices to burgers during the last 1 minute of grilling.
Top bun bottoms with ketchup, lettuce, onion, tomato, burgers, tortilla strips (if desired) and bun tops. Serve immediately.