1. Cut beef steak into 1-1/4-in. pieces. Combine marinade ingredients. Place beef and marinade in food-safe plastic bag; turn to coat. Close bag securely and marinate in refrigerator 6 hrs. or as long as overnight, turning occasionally.
2. Heat 2 tsp. oil in a large nonstick skillet over medium heat until hot. Add mushrooms; cook and stir until tender. Remove and keep warm. Meanwhile cook rice according to pkg. directions, omitting salt and butter. When rice is done, stir in mushrooms.
3. Soak eight 9-in. bamboo skewers in water 10 min.; drain. Remove beef from marinade; discard marinade. Alternately thread beef, onion, squash and pepper evenly onto skewers. Place on grid over medium, ash-covered coals. Grill, uncovered, 8-10 min. for medium rare to medium doneness, turning occasionally.
4. Serve kabobs over wild rice.
* Recipe Courtesy of The Beef Checkoff