Prepare potatoes: Select uniform-sized red or Yukon Gold potatoes, wash them thoroughly, and peel if desired. Cut into roughly 3/4-inch chunks.

Cook potatoes: Place potatoes in a large pot with 2 teaspoons kosher salt and cover with cold water, about 1 inch above potatoes. Bring to a boil, then reduce to a simmer. Cook for 8 to 10 minutes or until fork-tender.

Season warm potatoes: Drain potatoes and spread them in a single layer on a rimmed baking sheet. While still warm, sprinkle remaining 1/2 teaspoon kosher salt and 1 tablespoon apple cider or rice vinegar evenly over the potatoes. Let cool to room temperature for approximately 15 minutes.

Prepare mix-ins: If using, peel and dice 3 hard-boiled eggs. Dice 2 dill pickle spears or measure 1/4 to 1/2 cup pickle relish. Dice 2 stalks celery, mince 1 large shallot, thinly slice 2 scallions if desired, and finely chop fresh parsley, dill, or a combination (about 2 tablespoons).

Make dressing: In a medium bowl, combine 1/2 to 3/4 cup mayonnaise, 1 tablespoon Dijon or yellow mustard, remaining 1 tablespoon vinegar, freshly ground black pepper to taste, and optional grated garlic cloves and dill pickle brine if using. Stir well to create a cohesive dressing.

Combine salad: Add cooled potatoes to the dressing and fold gently to combine without mashing, preserving some texture. Fold in celery, pickles or relish, shallots, scallions, herbs, and eggs if using. Taste and adjust seasoning with salt, pepper, or additional vinegar as needed.

Chill and serve: Cover the bowl and refrigerate for at least 1 hour, up to 1 day, to allow flavors to meld. Before serving, stir gently and garnish if desired.