Combine 1/2 cup yogurt, ginger and garlic in small bowl. Place beef steaks and yogurt mixture in food-safe plastic bag; turn steaks to coat. Close bag securely and marinate in refrigerator 6 hours or as long as overnight, turning occasionally.
Meanwhile line a strainer with paper towels; set over small bowl. Place remaining 1 cup yogurt in strainer. Cover; let drain in refrigerator 30 minutes or as long as overnight to thicken.
Remove steaks from marinade; discard marinade. Place steaks on grid over medium, ash-covered coals. Grill, covered, 10 to 12 minutes (over medium heat on preheated gas gril, times remain the same) for medium rare (145°F) doneness, turning occasionally. (Do not overcook.)
Meanwhile combine thickened yogurt and wasabi paste. Set aside.
Carve steaks into thin slices; season with salt and pepper, as desired. Serve with wasabi- yogurt mixture.
Nutrition information per serving: 195 Calories; 45 kcal Calories from fat; 5 g Total Fat; 2 g Saturated Fat; 2 g Monounsaturated Fat; 57 mg Cholesterol; 9 mg Sodium; 6 g Total Carbohydrate; 0 g Dietary Fiber; 29 g Protein; 2.2 mg Iron; 4.6 mg Niacin; 0.4 mg Vitamin B6; 1.8 mcg Vitamin B12; 5 mg Zinc; 31 mcg Selenium;