1. For the marinade, combine lime juice, olive oil, 1/2 teaspoon salt, 1/4 teaspoon pepper, and 1/4 teaspoon cumin in small bowl. Place salmon in 10-inch microwave proof glass pie plate. Brush each fillet with marinade. Cover with plastic wrap and let stand at room temperature 30 minutes.
2. For the Ginger Sauce, combine ginger, garlic, tomato, and the 1/4 teaspoon cumin in 1-quart microwave proof bowl. Microwave on 100 percent power (High) 30 seconds; stir in yogurt, green onion, chopped mint, red pepper sauce, 1/4 teaspoon salt, and 1/8 teaspoon pepper. Set aside.
3. Turn back one section of plastic wrap covering salmon. Microwave on 100 percent power (High) 2 minutes. Rotate plate; microwave 1 to 2 minutes more or until fish flakes easily with a fork. Let stand, covered, 2 minutes.
4. Place salmon fillets on 4 serving plates; spoon ginger sauce on top. Garnish each serving with lime wedges and mint sprig, if desired. Makes 4 servings.