Grilled Chicken Breast with Honeydew Salsa

1 1/3 cups finely diced peeled seeded honeydew or other melon 1/4 cup finely chopped fresh cilantro plus 1/4 cup cilantro leaves 1/4 cup finely diced red onion 2 tablespoons fresh lime juice 2 tablespoons olive oil 2 teaspoons finely grated lime peel 1 teaspoon finely chopped seeded serrano chile Nonstick vegetable oil spray 4…