Prepare marinade by stirring together first 10 ingredients (through salt & pepper). Let chicken soak in marinade for 2 hours.
Cut chicken into pieces for kebabs.
Toss bell peppers, zucchini and red onion in 2 tablespoon olive oil.
Soak wooden skewers in water for 30 minutes.
Preheat grill to medium-high heat.
Thread chicken pieces, peppers, zucchini and onions on the skewers.
Cook skewers 7-9 minutes, or until chicken reaches 165 degrees F in the center. Turn after about 4 minutes.
Prepare the tzatziki sauce by placing chopped cucumber in a strainer and sprinkle with salt (lightly). Let sit at room temperature for 30 minutes.
Squeeze cucumbers in a paper towel to drain the excess water, and then place in food processor. Pulse to finely chop.
Pour cucumbers into a large mixing bowl, add yogurt, garlic, lemon juice, olive oil, parsley and dill. Season with salt and pepper, to taste. Whisk all ingredients.
Drizzle tzatziki sauce over kebabs and enjoy!