Wash and cook the unpeeled potatoes for 20-25 minutes. Drain, let cool and peel them. Cut into fairly large slices.
Finely chop the onions.
Slice the pickles and the eggs.
For the sauce: combine the mayonnaise, water from the pickle jar and mustard.
Combine the sauce with the potatoes, onions, pickles and eggs.
Season to taste and let it all chill togetherĀ for at least 30 minutes.