Dissolve sugar in a bit of hot water. Add light and dark soy sauce, mix well, and reserve.
Bring water to a boil. Meanwhile, cut half of the ginger into slices, and julienne the rest. Cut scallions into sections.
Line the bottom of a heat proof dish with ginger slices and scallion whites, then lay the fish on top.
Place the dish into the pan of boiling water on a steaming rack. Cover and steam over a rolling boil for about 5 minutes, or until the flesh barely flakes.
While the fish steams, heat up the oil in another pan until it’s smoking hot.
Once fish is done, cover the top with julienned ginger and scallion greens. Pour the hot oil over everything, followed by the soy sauce mixture.
Optionally, garnish with cilantro. Serve hot.