Ask your fish store for a very fresh whole salmon with the head.
Wash fish thoroughly in cold water.
Large dice the onion, celery and carrot.
In a large roasting pan combine the wine, salt, carrot, celery, onion and bay leaves. Bring to a boil on the stovetop, then simmer for 30 minutes.
Meanwhile, make a cradle for the fish. Using two large pieces of extra heavy duty aluminum foil, fold the long edges together so it will fit in the length of the roasting pan. The sides will stick out of the pan. Poke holes in the foil (for draining the fish later).
Lay the fish in the cradle, and lower the cradle into the simmering wine in the roasting pan. Add hot water if necessary to cover the fish. Tightly cover the pan with more foil, and simmer gently for 30 minutes, or 10 minutes for each inch of fish thickness.
Refrigerate the entire pan overnight with the fish still in the cooking liquid.
Next day, arrange escarole and/or kale on a large serving platter.
Very gently remove the cradle with the fish on it from the roasting pan and drain. Discard any vegetables or bay leaves. The fish is VERY fragile right now.
Put the cradle on the counter next to the platter. Using both hands (and arms), gently slide the fish onto the serving platter.
Using a butter knife, scrape the skin and any grey bits from the body of the fish. Leave the head, tail and fins untouched. Remove the eye.
Spread cold mayonnaise over the body of the fish. This is your chance to cover up any boo-boos from moving the fish.
Slice the cucumber in very thin (1/8") slices. (I use a mandoline).
Arrange the cucumber slices over the body of the fish so they look like scales.
Insert a flower in the eye socket.
Serve with crackers or cocktail bread and dilled bearnaise.