In a large saucepan combine 1 sliced onion, salt, white pepper, and the cold water. Bring to a boil and reduce to a simmer. Gently slide in the salmon steaks and simmer for 15-20 minutes, until fish is done. Spread half the remaining sliced onions in a glass dish. Remove the salmon steaks from the poaching liquid (but save the liquid) and place on top of the onions and cover with the remaining sliced onions. To the poaching liquid in the saucepan, add the vinegar, sugar, pickling spice, pepercorns and bay leaf. Bring to a boil, reduce heat to a simmer, and cook for 5 minutes. Strain the stock and pour over the fish. Allow to cool completely, cover and refrigerate for 2 days. Serve cold as an appetizer or lunch dish. Pickled salmon will keep well, refrigerated, for up to a week.