Combine the onion, wine and water in a large skillet and bring to a simmer on medium heat. Add the salmon steaks and enough water to submerge the fish about 1/2 way. Reduce heat as necessary so that the liquid is just barely boiling.
Cook about 4 minutes, then turn steaks over carefully and finish cooking them through (approximately another 4 minutes). Cooking times will vary depending on the thickness of the fish, so please do verify.
Using a slotted spatula, carefully remove the fish from the pan and place on serving plates. Season to taste with salt and pepper.
Makes 4 servings.