Preheat broiler. Spray broiler pan with nonstick vegetable oil spray. Whisk yogurt, ginger and curry powder in medium bowl to blend. Season lamb with salt and pepper. Stir into yogurt mixture; let stand 5 minutes. Meanwhile, place onion rounds in shallow bowl. Sprinkle with salt and pepper. Drizzle with olive oil; toss to c-thick layer on broiler pan. oat. Spread out onion in 1/2-inch-thick layer on broiler pan. Thread lamb pieces onto 2 wooden skewers. Arrange skewers alongside onion. Broil lamb and onion about 5 inches from heat source until lamb is brown outside but still pink inside and onion is lightly charred, turning occasionally, about 10 minutes. Transfer lamb and onion to plates. Serve with lemon wedges.