For each serving, to order: Place 1 fish fillet on plate; sprinkle with 1 teaspoon mirin. Spread 2 teaspoons black bean sauce on fish; sprinkle with 1 tablespoon green onions and 2 teaspoons ginger. Place plate on steamer tray, cover and steam over simmering water about 5 minutes or until a knife can be easily inserted into thickest part of fish.