Grate the zest of the orange and squeeze the juice, put in a sauce pan together with the Campari, thyme and vanilla pod and bring to the boil. Add the peeled prawns to the cooking liquor and bring to the boil again, turn off the heat, cover and allow cooling in the liquid. Meanwhile, prepare the couscous according to pkt. instructions, fluff with a fork and mix in the extra virgin olive oil, tomato and parsley. Take a ring and place in the middle of a serving plate. Line the ring with overlapping slices of cucumber, half fill with the couscous mixture. Garnish with the prawn tails, chives and vanilla bean. Strain the cooking liquid and whisk in the mayonnaise. Drizzle the obtained sauce around the plate.