For salsa, in a small bowl, combine peaches, cucumber, 2 tablespoons preserves, onion, mint and 1/4 teaspoon salt.
Sprinkle chicken with pepper and remaining salt. On a lightly greased grill rack, grill chicken, covered, over medium heat 5 minutes. Turn; grill 7-9 minutes longer or until a thermometer reads 165°, brushing tops occasionally with remaining preserves. Serve with salsa.