Sauté the onions with the margarine until the onions are tender (clear). Stir in the half and half cream, wine, and dill, blend well.Cook the salmon as desired: (steam, bake, broil). Arrange the salmon on a serving platter and granish with some sauce and a sprig of dill weed or parsley. Serve the remaining sauce on the side, with steamed rice. Serves 4