In a medium bowl whisk together olive oil, lemon juice and zest, vinegar, garlic, oregano, basil, thyme, coriander, salt, and pepper.

Place chicken cubes in a large zip-top bag or shallow dish. Pour the marinade over, seal, and massage to coat evenly. Refrigerate for at least 45 minutes and up to 2 hours.

In a separate bowl toss bell pepper, zucchini, and red onion with 2 Tbsp olive oil, a pinch of salt, and the remaining oregano and basil.

For grilling, heat to medium-high (about 200 °C). For oven baking, preheat to 205 °C and set a rack in the upper third. If using wooden skewers, soak them in water for 30 minutes. Lightly oil grill grates or a baking sheet.

Thread pieces in this order: bell pepper, red onion, zucchini, two chicken cubes. Repeat the pattern twice per skewer and finish with a vegetable.

Grill method: Place skewers on hot grates and cook 4 to 6 minutes per side, turning once, until the thickest chicken pieces reach 73 °C.

Oven method: Arrange skewers on the prepared baking sheet and roast 16 to 22 minutes, turning halfway. For extra char, switch to the broiler for the final 2 minutes, watching closely.

Combine yogurt, grated cucumber, garlic, dill, lemon juice, olive oil, salt, and pepper in a small bowl. Mix well, cover, and refrigerate until serving.

Let cooked kebabs rest 5 minutes. Sprinkle with chopped parsley, add lemon wedges, and offer the chilled tzatziki on the side for dipping or drizzling.