Prepare Jerk Seasoning: In small cup, combine all seasoning ingredients. Several hours before serving, in 1-quart resealable plastic bag, combine chicken breasts and Jerk Seasoning. Refrigerate until ready to cook. Prepare Dressing: In jar with tight-fitting lid, combine olive oil, lemon and lime juices, sugar, pepper, and salt, shaking mixture until well combined. Refrigerate dressing until ready to serve. With serrated knife, cut away peel and membrane of each tangelo. Working over large bowl to catch and reserve juice, section tangelos and place in bowl. Add pineapple and mango. Cover and refrigerate at least 15 minutes or up to 3 hours. In large nonstick skillet, heat vegetable oil over medium heat. Add seasoned chicken breasts and cook until browned on bottom -- 4 to 6 minutes. Turn breasts over and cook until chicken is done -- 4 to 6 minutes longer. Remove to medium-size bowl and let cool to touch. When cool enough to handle, pull chicken apart into strips and coat with 1 tablespoon dressing. To serve, add watercress to fruit mixture. Place chicken in center of serving plate. Spoon fruit and watercress mixture around chicken and drizzle with remaining dressing.