Combine yogurt, garam masala, garlic powder, paprika and salt in small bowl. Spread 1/3 cup yogurt mixture over steak. Reserve remaining yogurt mixture for sauce. Place beef steak in food-safe plastic bag; turn steak to coat. Close bag securely and marinate in refrigerator 6 hours or as long as overnight.
Remove steak from marinade; discard marinade. Place steak on grid over medium, ash-covered coals. Grill, covered, 11 to 16 minutes (over medium heat on preheated gas grill, covered, 16 to 21 minutes) for medium rare (145°F) to medium (160°F) doneness, turning occasionally. Meanwhile, grill onion slices, covered, 11 to 15 minutes. Remove steak from grill; let stand 3 to 5 minutes.
Meanwhile, heat remaining sauce and water in small saucepan over medium heat 2 to 3 minutes. Cut steak lengthwise in half, then across the grain into thin slices. Cut onions into bite-sized pieces. Combine rice and peas in large bowl. Divide rice mixture evenly among plates. Serve with beef, onions and sauce.
Nutrition information per serving: 300 Calories; 63 kcal Calories from fat; 7 g Total Fat; 2.8 g Saturated Fat; 0.16 g Trans Fat; 0.6 g Polyunsaturated Fat; 2.8 g Monounsaturated Fat; 67.7 mg Cholesterol; 3.7 mg Sodium; 30.7 g Total Carbohydrate; 8.5 g Dietary Fiber; 30.7 g Protein; 2.7 mg Iron; 520.2 mg Potassium; 8.5 mg Niacin; 0.7 mg Vitamin B6; 1.6 mcg Vitamin B12; 5.3 mg Zinc; 31 mcg Selenium; 106.5 mg Choline;