Mix first three ingredients in a small bowl and set aside.
Pre-heat skillet over medium heat with cooking oil or non-stick spray. Add zucchini and stir for 3-4 minutes until zucchini is crisp-tender. Transfer to serving dish and cover to keep warm.
Add more oil to same skillet as needed, and increase heat to medium-high. Add chicken and cook for 3-6 minutes or until chicken is tender and no longer pink. Transfer chicken to covered serving platter and mix with zucchini.
Add dressing mixture and tomatoes to skillet, and cook for about 30 seconds, just enough to heat. Spoon tomatoes and dressing over chicken and zucchini.
Serve warm. Salt and pepper to taste.