Wash the salad. Cut radicchio into small pieces, pluck salad leaves into small pieces. Wash prawns and pat dry. Chop walnuts coarsely. Wash thyme, dab dry and remove leaves. Roast the walnuts and thyme in a hot pan and remove.
Heat the oil in a frying pan and fry the prawns for 2-3 minutes while turning. Season with salt and pepper. Remove from the pan and drain on kitchen paper. Add orange juice to the frying fat and bring to the boil once.
Pull off the stove. Stir in vinegar and season to taste with salt and pepper. Arrange salad with prawns on a plate. Garnish with orange slices. Sprinkle with walnut mixture and sprinkle with the vinaigrette.