Peel the oranges directly along the pulp so that the bitter white skin is removed.
Peel the onions and cut into wafer-thin slices. Remove the skin from the yellow sausage and cut into slices. Mix the white wine vinegar with salt, sugar, crushed garlic clove and oil.
Cut the oranges into slices and place in a bowl with the onion rings and yellow sausage slices. Pour the marinade on top and sprinkle with crushed green pepper.