Preheat grill pan or outdoor grill to medium-high to high heat.
Skewer each piece of chicken on a wooden skewer and set aside.
Combine coriander, cumin, cardamom, chili powder, paprika, a pinch of salt and pepper on a shallow plate or in a bowl then mix with lemon juice and EVOO. Grate in garlic, add chicken, turn in spices and let marinate for at least 15 minutes.
Grill chicken until marked on each side and cooked through, about 8-10 minutes depending on the thickness of the chicken.
When the chicken is done, place skewers on a platter, drizzle with tahini and sprinkle with sumac and sesame.