Clean and peel the prawns. Slice the courgettes very thinly lengthwise and brush both sides of each strip of courgette with a little oil. Wrap each prawn in a slice of courgette and secure with a cocktail stick. Place all the citrus juice in a saucepan and boil to reduce by half, chill. Heat a thick frying pan and fry the prawns, the oil coating the courgette should be sufficient for this, but if necessary add a little more oil. Mix the cold citrus juice with the oil and seasoning, dress the salad with this and place on individual plates. Arrange the prawns on the salad and garnish with orange slices, chives and extra vinaigrette.