Chop potatoes into 1 inch cubes. Put into stock pot with 2 tbsp salt and water to cover. Boil for 5 minutes or until potatoes are just fork tender. Drain.
Put hot potatoes in bowl. Add chopped onions and red wine vinegar. Stir to combine.
In a separate small bowl combine fresh dill, mayo, mustard and salt to taste. Use a stick blender to blend the ingredients.
When potatoes have cooled, add the mayo mixture and stir well. For added fun, add chopped hard boiled eggs, bacon or ham crumbles or chopped up, cooked sausage.