Boil potatoes, with skins on, until just tender. Drain and let cool.
When potatoes are cooled, peel and cut into bite-size pieces. Place in a large bowl.
Coarsely chop eggs. Add eggs and pickle chunks to potatoes.
Gently toss in mayonnaise. (Start with less mayo, and add more as needed to obtain consistency you prefer.) Be sure to toss lightly to avoid breaking up the potato too much.
Add salt and pepper to taste. Also add onion, if using. Stir gently again, just to combine.
At our house, we usually serve a small bowl of onion on the side so people can add as much as they like, or none at all.
