01 - In a large mixing bowl, whisk together the olive oil, lemon juice, Greek yogurt, minced garlic, red wine vinegar, dried oregano, dried thyme, salt, black pepper, and lemon zest until well combined.
02 - Add the cubed chicken to the marinade and toss to coat every piece thoroughly. Cover the bowl with plastic wrap and refrigerate for at least 1 hour, or up to 8 hours for deeper flavor penetration.
03 - If using wooden skewers, submerge them in water for at least 30 minutes to prevent burning on the grill.
04 - Thread the marinated chicken pieces onto the skewers, alternating with red onion chunks, bell pepper pieces, and zucchini rounds, distributing the ingredients evenly across each skewer.
05 - Preheat an outdoor grill or grill pan to medium-high heat. Lightly grease the grates with oil to prevent sticking.
06 - Place the skewers on the hot grill and cook for 6 to 8 minutes per side, turning once, until the chicken is cooked through and lightly charred on the edges.
07 - Transfer the kabobs to a serving platter and serve immediately with lemon wedges, a sprinkle of fresh parsley, and tzatziki sauce on the side.