1. Make a bed of the halved green onions on a plate large enough to hold the fish and suitable for steaming. Place the filets in a single layer on the bed of green onions. Cover and refrigerate until ready to steam.
2. Place a bamboo steamer on the bottom of a wok or large, deep frying pan and pour in water to a depth of 2 inches. The water should not touch the steamer. Bring the water to a boil over high heat.
3. Meanwhile, in a bowl, stir together the ginger, garlic, 1 tablespoon of the canola oil, light soy sauce, sesame oil, dark soy sauce, oyster sauce, sugar, cornstarch, and white pepper. Spoon the mister evenly over the fish fillets.
4. Place the plate on the steamer above the boiling water, cover tightly, and steam the fish over high heat for 10 minutes per inch thickness. Carefully remove the plate from the steamer and transfer the fish fillets to a warmed platter. Discard the bed of green onions and spoon any sauce remaining on the plate over the fish.
5. In a small pan over high heat, heat the remaining 1 tablespoon of canola oil until it is almost smoking. Place the julienned green onion on top of the dish. Carefully drizzle the hot oil over the fish and serve with the rice.