Heat wine, water, lemon, dill and peppercorns on medium heat in a sauté pan until close to boiling.
Reduce heat to a bare simmer. Using a spatula, place salmon fillets in liquid a single layer. Cover and simmer for 10 minutes, or until fish flake easily with a fork.
Chill salmon in the refrigerator. While salmon is chilling, combine yogurt, lemon juice, mustard and dill in a small bowl.