Tip the mince, sumac, cumin, garlic and lemon zest into a bowl, season and combine using your hands. Form into 10 small balls, about 30g each. Heat the oil in a pan over a medium heat and fry the balls for 8-10 mins, shaking the pan now and then until browned and cooked.
Combine the cabbage, mint, onion, cucumber and pomegranate seeds with the lemon juice. Season. Stuff the slaw and meatballs into the pittas and serve with the yogurt.