01 - In a large mixing bowl, combine olive oil, lemon juice, Greek yogurt, minced garlic, red wine vinegar, oregano, thyme, salt, black pepper, and lemon zest. Whisk until fully blended.
02 - Add chicken cubes to the marinade and mix thoroughly to ensure even coating. Cover the bowl and refrigerate for a minimum of 1 hour, and up to 8 hours for optimal flavor absorption.
03 - If using wooden skewers, submerge them in water for 30 minutes to prevent burning during grilling.
04 - Thread marinated chicken pieces, red onion, red bell pepper, yellow bell pepper, and zucchini alternately onto skewers, distributing ingredients evenly.
05 - Preheat grill or grill pan to medium-high heat. Lightly oil the cooking grates to prevent sticking.
06 - Arrange skewers on the grill and cook for 6 to 8 minutes per side, turning once, until chicken is cooked through and vegetables are slightly charred.
07 - Transfer kabobs to a serving platter. Garnish with lemon wedges, sprinkle with chopped parsley, and serve with tzatziki sauce as desired.