In a 4-cup glass dish, combine soy sauce, agave, Shaoxing wine, sliced ginger, scallions, and peanut oil, and stir gently.
Add the fish, skin-side up.
Cover but leave open enough to allow steam to escape. Microwave at 50% Power for 4-5 minutes (will probably need more with our microwave), or until the fish is just barely cooked through and is tender when poked with a chopstick.
Let it rest for 2 minutes with the lid on to gently continue steaming.
Serve with sauce and garnish with more sliced green onions, if desired.
