Add the rice wine, soy sauce, chopped ginger and sesame oil, and toss lightly to coat.
Cover with clingfilm and leave to marinade in the fridge for 10 minutes.
Arrange the fish on a heatproof plate, with the marinade, and place in a steamer. Steam over simmering water in a covered wok for 5-8 minutes, or until the fish flakes when the skin is pressed firmly or the dorsal fin pulls out easily.
Remove the fish from the steamer and place in a heatproof platter.
Heat a wok over high heat, add the oil and heat until smoking.
Sprinkle the steamed fish with the spring onion, shredded ginger and pepper, and slowly pour the hot oil over the fish.
This will cause the skin to crisp, and cook the garnish.