Marinate the Chicken:
In a mixing bowl, whisk together olive oil, lemon juice, garlic, vinegar, oregano, paprika, cumin (if using), salt, and pepper.
Add the chicken cubes to the marinade, toss to coat, and cover. Refrigerate for at least 30 minutes or up to 4 hours for maximum flavor.
Prepare the Skewers:
If using wooden skewers, soak them in water for 30 minutes to prevent burning.
Thread the marinated chicken onto skewers, leaving a little space between each piece for even cooking.
Grill the Chicken:
Preheat your grill or grill pan over medium-high heat. Lightly oil the grates to prevent sticking.
Place the skewers on the grill and cook for 10–12 minutes, turning occasionally, until the chicken is cooked through and has a slight char.
Assemble and Serve:
Serve the chicken skewers hot with warm pita bread, fresh vegetables, and a generous dollop of tzatziki sauce. Garnish with parsley or dill if desired.