Rinse trout and pat dry, inside and out. Brush inside and out with oil. Lay trout, spread open and skin side down, in a single layer in two 10x15 inch baking pans. Drizzle sherry evenly over trout; sprinkle with ginger. Cover pans tightly.
Bake at 400* F for 8-10 minutes, or until fish is opaque in thickest part (flake gently with a fork to test) but still moist-looking.
Transfer to a platter or plates, using two wide spatulas to carefully lift each trout (if they start to break up, cut fillets apart and transfer each fillet seperately).
Drizzle 2 tbsp soy sauce evenly over trout. Sprinkle evenly with green onions and cilantro. Serve with additional soy sauce to taste.