In a small bowl, mix together the cumin, paprika, garlic powder, coriander, cardamom, ginger, turmeric, aleppo peppers, cinnamon, and ground cloves to make a shawarma spice mix.
Add the spice mix, along with olive oil and lemon juice to a bowl with the chicken thighs. Season with salt and pepper. Marinate for at least 2 hours.
While the chicken is marinating, make the shawarma sauce by stirring together the yogurt, garlic, tahini, and lemon juice. Taste and season with salt and pepper. Cover and set aside in the fridge until ready to eat.
Heat up a cast iron or heavy bottomed frying pan over medium-high and cook the chicken for 3-4 minutes per side until caramelized and cooked through.
Slice the chicken into bite sized pieces and enjoy hot on a platter with shawarma sauce, rice, salad, and a pita; or place the shawarma in a pita with lettuce, tomatoes, cucumbers, onions, and drizzle with shawarma sauce. Optional: After slicing the chicken into bite sized pieces, and add back to the pan and cook over high heat to add extra char before serving.