Spray large skillet with cooking spray; heat over medium heat until hot. Add chicken and cook 10 to 15 minutes or until well browned and no longer pink in center. Cut chicken into strips or cubes. Combine chicken, zucchini, bell pepper, mandarin oranges and orzo in large bowl; drizzle with Citrus Vinaigrette and toss. Cover and refrigerate at least 2 hours or overnight. Stir in raisins just before serving. Season to taste with salt and black pepper.