Slice off the top and bottom of the oranges, then peel all round the fruit down to the flesh. Cut out the fruit segments between the white membranes. Combine the lemon zest and juice with the oil, season. Mix in the chicory and grapefruit segments, arrange the salad on plates. Garnish with chopped peanuts before serving.
Heat a little oil in a wide-bottomed, non-stick frying pan. Reduce the heat, fry the prawns on a medium heat for around 1½ mins. on each side, remove, season, and serve on top of the salad.