Thinly slice the onion and finely chop the garlic. Cut the red pepper into small cubes.Cut the green beans into 3 pieces.
Heat the oil in a frying pan, then gently sauté the onion and red pepper over low heat for 5 about minutes until soft.
Add the garlic and oregano and stir for a minute. Add the green beans and half a glass of water. Cover with a lid on and cook for 5 minutes.
Add the mustard and vinegar then the drained beans. Season to taste then stir to combine.
Meanwhile, slice the sausages, then fold in with the beans.
Heat through, then stir in the parsley just before serving.