Turkish kebabs with tomato chilli sauce

Name: Turkish kebabs with tomato chilli sauce
Ingredients: 2 garlic cloves; 200g Greek yogurt; 1 lemon, juiced; 2 tsp tomato purée; 2 tsp chilli flakes (Aleppo are nice); 2 tsp sumac; 4 chicken breasts, cut into chunks; 300g baby plum tomatoes; 1 thumb-sized red chilli, stem removed; 2 tbsp extra virgin olive oil; 1 small red onion, sliced; 1 tbsp pomegranate molasses; 4 Middle Eastern flatbreads; long pickled chillis (guindillas); a handful fresh coriander; a handful fresh flat-leaf parsley