Cut head and tail from salmon; set aside.
Cut salmon in half lengthwise; remove pin bones with tweezers or needle-nose pliers. Slice crosswise into 2-inch pieces; cover and set aside.
Place head and tail in a 4-quart saucepan. Cover with 5 cups water; add wine and next 6 ingredients. Bring mixture to a boil. Reduce heat, and simmer 30 minutes. Pour mixture through wire-mesh strainer into a bowl, discarding solids. Return liquid to pan. Stir salt into liquid.
Pour liquid into a fish poacher*; bring to a boil. Reduce heat, and simmer gently. Arrange fish on poacher insert, and place in liquid. Simmer 10 minutes; remove from heat, and let stand 5 minutes.
Remove salmon, and place on serving plates. Top with Cucumber Beurre Blanc and chopped cucumber. Serve with steamed fresh vegetables.
*If you don't have a fish poacher, use a roasting pan large enough to hold the salmon in a single layer. Place salmon in gently simmering water with a metal spatula.