Mix together the yogurt, onion, red wine vinegar, minced parsley, cumin, garlic, smoked paprika, cinnamon and sea salt to make the chicken shawarma marinade.
Toss the chicken thighs in the marinade until all pieces are well covered.
Place the chicken in a plastic bag or other storage container and keep in the fridge to marinate for 6-12 hours.
Heat your oven to 400℉Place a wire baking rack over a large baking sheet then place the chicken on top of of it in a flat single layer.Bake for 20-25 mins then remove from the oven.
Set the oven to broil.Remove the chicken from the baking sheet to a large cutting board and cut the thighs into strips.Place the cut chicken on the baking sheet and put under the broiler for 5-10 minutes, or until the top of the chicken begins to crisp a bit.
To make the parsley tahini:
Put the tahini, water, garlic, salt, lemon juice and parsley in a blender or food processor.
Blend until smooth then serve with the chicken shawarma