Mix the tandoori seasoning in a medium size bowl with the yoghurt and salt.
Gently stir in the prawns until they are all well coated with the yoghurt/tandoori mixture, then cover and marinate in the fridge for several hours, or at room temperature for 30 minutes.
In the meantime, soak 12 bamboo skewers in water for at least 30 minutes.
Thread four prawns onto each skewer, piercing each prawn through the tail end and the head end of the body, so it sits like a C on the skewer.
Grill on a pre-heated barbecue, brushing with left-over marinade as they cook. Be careful not to overcook the prawns.
These tandoori prawn skewers are ideal party food. They can be removed from the skewer and arranged on a plate, so that each one can be held by the tail and eaten in the fingers. Alternatively, serve a couple of skewers on steamed rice.