Mix steak sauce and 1/2 tsp. red pepper; pour 1/4 cup steak sauce mixture over steak in shallow glass dish. Refrigerate 30 min. to marinate, turning after 15 min. Meanwhile, refrigerate remaining steak sauce mixture.Heat grill to medium heat. Remove steak from marinade; discard marinade. Grill steak 17 to 21 min. or until medium doneness (160ºF), turning and brushing occasionally with remaining steak sauce mixture. Meanwhile, combine remaining ingredients. Remove steak from grill to cutting board. Let stand 5 min. before cutting across grain into thin slices. Serve topped with cucumber mixture.