In a bowl,mix the vinegar,water,sugar and first measure of salt together. Stir to dissolve. Cut the carrots into strips lengthways,or use a julienne peeler to cut them into matchsticks. Cut the cucumber into thin rounds. Add to the vinegar. Leave to sit in the fridge for at least an hour.
To cook the rice,place the coconut milk,water and second measure of salt in a saucepan. Bring to a simmer and add the rice. Cook for 10-12 minutes over a low heat,just simmering with the lid on until just cooked,then remove from heat. Place a clean tea towel over the top and leave to steam for a further 10 minutes.
In the meantime,thread the prawns on skewers,4 per skewer. Place in a shallow baking dish and rub with the oil and finely chopped chilli.
Heat a griddle pan over a high heat and when smoking hot add the prawn skewers. Cook for 2-3 minutes on each side,or until just cooked with some char lines. Scatter with the soy sauce and sesame seeds.
Serve the rice on a platter with the pickles,peanuts,prawn skewers,sliced chilli and herbs. Serve with a spicy sambal or sweet chilli sauce.