Chipotle salsa - both a key ingredient in the marinade and a condiment for the meat and vegetables - has a smokier, more full-bodied flavor than regular tomato salsa. Marinating the vegetables in a zip-top plastic bag eliminates cleanup - you can just throw the bag away. Because the steak has to marinate from four hours to overnight in order to tenderize and absorb flavor, you'll need to start this recipe ahead of time.
Combine first 7 ingredients in a large zip-top plastic bag. Seal and marinate in refrigerator 4 hours or overnight, turning occasionally.
Prepare grill or broiler.
Remove the steak and vegetables from bag; discard marinade. Place the steak and the vegetables on grill rack or broiler pan coated with cooking spray; cook 7 minutes on each side or until desired degree of doneness. Cut steak diagonally across the grain into thin slices. Cut peppers into thin strips. Cut onion slices in half.
Warm tortillas according to package directions. Divide steak, bell peppers, and onion evenly among tortillas; roll up. Top each serving with 1 tablespoon chipotle salsa and 1 1/2 teaspoons cilantro. Serve immediately.