Combine first 6 ingredients in a heavy-duty, zip-top plastic bag; seal bag, and shake well. Seed green and sweet peppers; cut each into 8 wedges. Place pepper wedges, steak, and onion in bag; seal bag, and shake. Marinate in refrigerator 8 hours. Combine tomato and next 5 ingredients. Cover and chill.
Remove steak and vegetables from marinade, reserving marinade. Thread vegetables onto 4 (10-inch) metal skewers. Coat grill rack with cooking spray; place on grill over medium-hot coals (350° to 400°). Place steak and skewers on rack. Grill vegetables, covered, 12 minutes or until tender, turning and basting occasionally. Grill steak 5 to 6 minutes on each side or to desired doneness, basting occasionally. Wrap tortillas in aluminum foil. Grill, covered, 2 minutes.
Cut steak diagonally across grain into 1/4-inch-wide slices. Divide steak and vegetables among tortillas. Top each with 3 tablespoons tomato salsa mixture; roll up tortillas.