Place fish on a larger platter that will fit in a wok or steamer and that has a lip that will contain the sauce.
In a small bowl, combine ginger, garlic and black beans. Evenly distribute the mixture on top of the fish.
In the same bowl, combine the sauce ingredients. Drizzle the sauce over the fish.
Carefully pour the oil mixture over the fish.
Fill a wok or steamer with enough water to just below the height of a trivet and bring it to a boil. Turn the heat down to medium. Place the platter on a trivet in the boiling water. Cover with a lid and let steam for 12-15 minutes.
Carefully remove the lid from the wok or steamer without dripping water into the dish. Check doneness by poking a chopstick through the thickest part of the fish. If there is no resistance, the fish is cooked through.
Sprinkle the remaining green onions and cilantro evenly over the fish. Cover with the lid for 30 seconds, until herbs have wilted.
Carefully remove the platter from the wok.
In a small saucepan on medium heat. Add vegetable oil and heat until you see a whip of smoke. Turn off the heat. Add 1 teaspoon sesame oil. Pour the hot oil over the dish and serve.