In a large mixing bowl, combine the thinly sliced chicken thighs with olive oil, lemon juice, white vinegar, minced garlic, grated ginger, Greek yogurt, ground cumin, ground coriander, smoked paprika, turmeric powder, ground allspice, ground cinnamon, cayenne pepper, salt, and black pepper. Mix thoroughly until all chicken pieces are evenly coated.

Cover the bowl tightly with plastic wrap and refrigerate for at least 4 hours, or preferably overnight, to allow the flavors to penetrate the chicken and tenderize it.

In a small bowl, whisk together the tahini, plain Greek yogurt, lemon juice, minced garlic, and a pinch of salt. Gradually add cold water, 1 tablespoon at a time, whisking constantly, until the sauce reaches your desired creamy, pourable consistency.

Taste and adjust seasoning if necessary. Cover and refrigerate until ready to serve.

Heat a large skillet or cast iron pan over medium-high heat. Once hot, add 1-2 tablespoons of cooking oil (if needed, although the chicken marinade already has oil).

Add the marinated chicken in a single layer, ensuring not to overcrowd the pan. Cook in batches if necessary. Allow the chicken to sear undisturbed for 4-5 minutes until deeply browned and caramelized on one side.

Stir and continue cooking for another 5-7 minutes, breaking up any clumps, until the chicken is cooked through, slightly crispy, and juicy. The total cooking time per batch should be about 10-12 minutes.

Remove the cooked chicken from the pan and set aside. Repeat with any remaining chicken batches.

Warm the pita bread or flatbreads according to package instructions.

To assemble your shawarma, spread a generous amount of the tahini-yogurt sauce on a warm pita. Pile with cooked chicken shawarma, then top with chopped tomatoes, cucumbers, red onion, fresh parsley, and sliced pickles.

Fold or roll the pita tightly and serve immediately. Enjoy your homemade chicken shawarma!