Bring 2 1/2 cups water to boil in covered pot. When water boils, turn off heat; add bulgur and allow to absorb water--15 minutes. Peel carrots and jicama. Wash and trim cucumber; do not peel. Julienne carrots, jicama, and cucumber. Drain off excess liquid. In serving bowl, beat oil with orange and lime juices and mustard. Stir in garlic, basil, tomato, and julienne vegetables. Dice chicken and add to vegetable mixture. Drain bulgur thoroughly and press out excess water; stir into vegetables. Season with pepper and salt, if desired. Top with walnut.