Preheat grill to medium-high heat. Toss 1 1/2 pounds small red potatoes with 1 teaspoon kosher salt and 2 teaspoons olive oil. Place potatoes 1/4 inch apart on grill rack coated with cooking spray. Grill 15 minutes; turn over with tongs. Grill 15 minutes or until done. Cool slightly. Cut potatoes in half; toss with 1/3 cup thinly sliced mint leaves.