Preparation Whisk miso, 1/4 cup mirin, 2 tablespoons vinegar, ginger, and 2 teaspoons sesame oil in small bowl to blend. Place fish in 8x8x2-inch glass baking dish. Pour miso mixture over; turn to coat. Let stand 30 minutes at room temperature. Preheat broiler. Line baking sheet with foil; brush with 1 teaspoon oil. Place fish on foil; pour marinade over fish. Broil until fish is cooked through and brown in spots, about 6 minutes. Meanwhile, mix remaining 1 teaspoon mirin, 1 tablespoon vinegar, 1 teaspoon sesame oil, and 1/4 cup green onions in medium bowl. Add sunflower sprouts; toss to coat. Divide salad among 4 plates; top with fish and sprinkle with remaining green onions.