Cook Potatoes for 30 minutes or until tender.
Drain Potatoes.
Rinse Potatoes with cold water; cool completely
Cut into small pieces; place in a large bowl
Add onions, parsley and 3 Tablespoons vinegar; toss
Cook sausage in olive oil for 5-10 minutes or until it begins to brown
Add Sausage to potato mixture.
To drippings in skillet, add mustard, garlic, pepper, cayenne pepper and remaining vinegar; bring to a boil, stirring with whisk constantly.
Pour over salad; toss gently.
Serve Warm.