Wash fish thoroughly with water. Pat dry with paper towels.
If using a whole fish, score the middle part with 2 to 3 slits.
Marinate the fish for 30 minutes with lemon juice, rice wine, soy sauce, salt and black pepper all over and inside. Do not marinate longer than 30 minutes or you will end up with kinilaw or ceviche.
In a small bowl, combine the onions, scallions, ginger and black pepper corns. Stuff the inside cavity of the fish. If there are leftover chopped onions, scatter them on top of the fish.Sprinkle the sesame oil on top and inside the fish. To cook stove-top in the steamer: Fill the bottom pot of the steamer with water. Cover and over high heat bring water to a boil.Place the fish on a platter which has a narrow rim, and which will fit inside the steamer.
Place the platter of fish inside the second level of the steamer. Cover and steam for 30 minutes for this size of fish ( 2 to 2.5 lbs.).
When fish is done, remove from steamer. Garnish with additional sliced scallions and fresh chopped parsley plus lemon slices. Serve warm with rice and a side of patis (fish sauce).
Cook's comments: When buying fish at the market, the fish monger offers to clean, remove the scales, intestines and tails of the fish. They also offer to fillet it. All these services are for free. Take advantage and have them do it for you before you head home from the market.