Grilled Salmon with Tangy Cucumber Sauce

Salmon, once a common staple in northeastern waters, remains a traditional Independence Day dish in New England. This recipe features a classic combination of salmon, cucumber and horseradish. Use two spatulas to make the salmon easier to cook. Garnish with lemon wedges if desired.
Combine the first 6 ingredients in a medium bowl. Add 1/4 teaspoon salt; mix well. Cover and chill for 30 minutes.Cook on the grill.Sprinkle the fish with the remaining 1/2 teaspoon salt and pepper. Place the fish skin-side up on a grill rack greased with cooking spray; cook for 3 minutes. Turn the fish a quarter turn (45 degrees) to create diamond-shaped cuts. Cook on the grill for 3 minutes. Turn the fish over; grill for 4 minutes or until desired browning. Serve with the sauce and dill sprigs, if desired.