Soak four 10-inch bamboo skewers in water 10 minutes; drain. Cut beef Top Sirloin Steak into sixteen 1-1/4-inch pieces.
Alternately thread beef and onion pieces evenly onto skewers. Set aside.
Combine preserves, vinegar, oil, garlic, salt and pepper in small bowl; reserve 1/4 cup for dipping. Brush kabobs with some of remaining sauce.
Place kabobs on grid over medium, ash-covered coals. Grill, covered, 7 to 11 minutes (over medium heat on preheated gas grill, 8 to 13 minutes) for medium rare (145°F) to medium (160°F) doneness, turning and basting with sauce every 2 minutes.
Season kabobs with salt, as desired. Serve with reserved sauce for dipping.
Nutrition information per serving: 209 Calories; 63 kcal Calories from fat; 7 g Total Fat; 2 g Saturated Fat; 0 g Trans Fat; 0.6 g Polyunsaturated Fat; 4.1 g Monounsaturated Fat; 56 mg Cholesterol; 339 mg Sodium; 13 g Total Carbohydrate; 1.9 g Dietary Fiber; 22 g Protein; 1.8 mg Iron; 419 mg Potassium; 6.2 mg Niacin; 0.5 mg Vitamin B6; 1.2 mcg Vitamin B12; 4 mg Zinc; 24.7 mcg Selenium; 83.4 mg Choline;