Arrange a layer of watercress, then cucumber and capsicum and radish on a round flat plate.
In a fry pan, heat up the oil on a high heat, add garlic, lightly brown.
Add prawns to the pan, season with salt and pepper. Add wine and cook, until most of the wine has evaporated (about 2 minutes), flipping the prawns over. Allow prawns to pink slightly. Add Arak, and watch out for flambol to rise. Lower heat, add chopped onion. Prawns should be just about cooked. They be slightly firm but not rubbery. cook on low for about 3 minutes, remove from heat, place on prepared dish, and pour over the rest of the cooking liquid on top. Serve with a slice of lemon.