In a small bowl, cover the mushrooms with boiling water. Set aside to soak until softened, 15 to 30 minutes. Remove the mushrooms and discard the water. Cut away and discard the stems and julienne the caps. Set aside.
Set a bamboo steamer in a wok filled halfway with water, and place the wok over high heat. Put a heatproof oval plate in the center of the steamer rack and place the fish on top. Scatter the mushrooms and scallions on top. Then sprinkle the salt, pepper and ginger. Place the lid on top, and cook until the fish flakes, 15 to 20 minutes.
Remove the plate from the wok and drain off any water, being careful the fish does not slip off the plate. While the fish is still very hot, drizzle the vegetable oil on top, followed by the soy sauce, sesame oil and wine, in that order. Garnish with the cilantro and serve.
To serve, make an incision with a knife along the body of the fish to the end of the tail. With a spoon, carefully push each half to the side. Lift off the bones and cut the bottom fillet into two pieces. Serve the fish in individual portions with some cilantro, mushrooms and sauce on the plate.