Place the yoghurt, chilli, spices, lime juice and garlic into a bowl and stir to combine.
Add the prawns and place into the fridge to marinate for two hours.
Heat a griddle pan until very hot and drizzle with the vegetable oil. Preheat the grill to its highest setting.
Remove the prawns from the marinade and thread onto metal skewers.
Place the prawn skewers onto the hot griddle and cook for three minutes on both sides, basting regularly with the lemon juice.
Meanwhile grill the flatbread under the grill until warmed through, then cut it into wedges.
To serve, place the prawn skewers onto plates with the flatbread pieces alongside. Sprinkle with fresh coriander and sesame seeds and garnish with lime wedges.