In a large bowl, stir together the Greek yogurt, garlic, tomato paste, lemon juice, oil, salt, cumin, paprika, cinnamon, black pepper, and cayenne pepper until the spices are well-blended into the yogurt.
Add the chicken pieces and mix until the chicken is well-coated with the marinade. Allow the chicken to marinate for 30 minutes or for up to 24 hours in the refrigerator.
Remove the chicken from the marinade and place in a single layer in the air fryer basket. Set the air fryer to 370ºF and cook the chicken for 10 minutes.
Open the air fryer and flip over the chicken. Set the air fryer to 370ºF and cook the chicken for another 5 minutes.
Test with a meat thermometer to ensure the chicken has reached an internal temperature of 150ºF before serving.
These only need to marinate for 30 minutes, but overnight is best. Ideally make the marinade the night before and let them sit in the fridge until you're ready to cook the next day.
You don't have to cook these on a skewer. Serve them as little bites of chicken, or place them on a skewer after their cooked for presentation.