Mix the oil and remaining ingredients up to and including salt, set aside.
Boil the lentils in water for approx. 5 mins., drain. Heat the oil in the same pan, sauté the onion, add the lentils and continue to sauté for approx. 3 mins., add the vinegar, salt to taste and divide onto plates.
Heat the oil in a frying pan, salt the prawns and fry in batches for approx. 3 mins. Arrange the prawns on top of the lentils, drizzle with chilli oil.