1 1/2 cups plain low-fat yogurt
1/2 cucumber, peeled, seeded and diced
2 tablespoons finely chopped fresh mint leaves
1 small clove garlic, finely chopped
Salt and pepper
4 6-oz. salmon fillets, about 1 inch thick
Pour yogurt into a strainer set over a bowl. Cover with plastic wrap, refrigerate and let drain until thickened, about 2 hours. Discard liquid in bowl, spoon yogurt into another bowl and stir in cucumber, mint, garlic, and salt and pepper to taste.
Preheat a gas grill on high, covered, for 10 minutes, then turn heat to medium. Oil a grill rack. Sprinkle salmon fillets with salt and pepper. Place salmon fillets, flesh side down, on oiled rack and cook, covered, for 4 minutes. Turn salmon carefully and continue to grill until just cooked through, 4 to 6 minutes longer. Serve with yogurt sauce on the side.
more at http://www.myrecipes.com