In a bowl, combine olive oil, lemon juice, minced garlic, paprika, cumin, dried oregano, salt, and pepper and tzatziki. Mix well to create a marinade.
Add the chicken cubes to the marinade, ensuring they are evenly coated. Allow the chicken to marinate in the refrigerator for at least 1 hour (or overnight for maximum flavor).
If you're using wooden skewers, soak the skewers in water before using.
Preheat your grill to medium-high heat.
Thread the marinated chicken onto the skewers, alternating with your favorite veggies like bell peppers, onions, and cherry tomatoes.
Place the skewers on the preheated grill and cook for about 10-12 minutes, turning occasionally, until the chicken is cooked through and has a beautiful char. Make sure the chicken reaches a temperature of 165 degrees.
Remove from the grill and let the skewers rest for a few minutes before serving.
Garnish with fresh herbs and serve hot with your favorite dipping sauce or alongside a refreshing salad.