In a large bowl, combine olive oil, lemon juice, chopped parsley, minced garlic, cumin, paprika, salt, and black pepper. Add chicken pieces and marinate for 15-20 minutes.
Preheat grill to medium-high heat.
Thread marinated chicken, red bell pepper, and red onion onto skewers.
Grill kebabs for 8-10 minutes, turning occasionally, until chicken is cooked through and vegetables are charred.
In a small bowl, combine Greek yogurt, mayonnaise, lemon juice, minced garlic, salt, and pepper. Stir until well combined.
Serve grilled chicken kebabs with garlic sauce.
Enjoy!