1. In a mixing bowl, combine olive oil, cumin, coriander, paprika, turmeric, cinnamon, salt, and pepper.
2. Add chicken thighs to the bowl and coat well with the spice mixture. Marinate for at least 1 hour.
3. Preheat the grill to medium-high heat. Grill the chicken for 6-7 minutes on each side or until fully cooked.
4. In a small bowl, mix yogurt, tahini, lemon juice, and minced garlic to make the sauce.
5. Slice the grilled chicken into thin strips.
6. Warm the pita bread on the grill for 1-2 minutes.
7. Assemble the sandwiches by spreading the sauce on the pita bread, adding chicken strips, lettuce, tomatoes, and cucumber.
8. Roll up the pita bread and serve immediately.