Park Deli was the place for the best sandwiches and salads growing up. Their potato salad was a favorite. It's a simple potato salad with just a few ingredients. It's tangy and creamy and so good with a sandwich.
Add the potatoes to a large pot and fill with cold water and 1 teaspoon of salt.
Bring to a boil and simmer until the potatoes are fork-tender, about 30 minutes. Let cool slightly and peel. Add the onion to a medium-size bowl. Add the water, vinegar, salt, and sugar. Whisk to combine.
Slice the warm potatoes to about ¼-inch thick. Place in a large bowl. Pour the onion-vinegar mixture over the warm potatoes.
Let the potato salad sit for approximately 10 minutes so that the potatoes can absorb some of the liquid. There will be a little liquid left. This is what makes this salad so nice and creamy. Add the mayonnaise and stir gently so not to break up the potatoes. Chill for at least 2 hours.