Directions

1. Make watermelon glaze: Place watermelon chunks in a food processor and blend until very smooth. Pour into a medium saucepan. Add red pepper jelly, 2 tablespoons lime juice, and the soy sauce. Bring to a boil and cook, stirring occasionally, until sauce is glossy and slightly thickened, 12-15 minutes. (The consistency will be like marinara sauce — thick enough to use as a mopping sauce for the chicken.)
2. While the glaze cooks, make cucumber-watermelon salad: In a medium bowl, stir together diced watermelon, cucumber, jalapeño, red onion, and cilantro. Whisk together lime zest, remaining 3 tablespoons lime juice, the olive oil, and cayenne in a small bowl. Pour over the watermelon mixture and toss to coat. Season with about ¼ teaspoon each salt and pepper. Refrigerate until ready to serve.
3. Preheat a grill to medium heat (350°-400°F). Sprinkle chicken all over with about ½ teaspoon salt and ¼ teaspoon pepper. Place chicken, skin side down, on hot grill. Cover grill and cook chicken 10 minutes. Baste with half the watermelon glaze. Grill, covered, until chicken is browned on underside, about 5 more minutes. Turn chicken over. Grill, covered, turning as needed to prevent burning and basting with remaining glaze after 10 minutes, until chicken reaches 165°F in the thickest part on an instant-read thermometer or juices run clear, 5-10 more minutes.
4. Transfer chicken to a platter or plates. Give the cucumber-watermelon salad a stir, then spoon some over the chicken and serve the rest on the side.