Cut the potatoes into ¾-inch chunks and place them in a large pot. Sprinkle with kosher salt and cover with cold water.

Bring the water to a rolling boil, then reduce heat to a simmer and cook for 8-10 minutes until fork-tender. Drain and cool on a baking sheet for 15 minutes.

Chop optional hard-boiled eggs, dill pickles, celery, shallot, and scallions. Add them to a mixing bowl.

In the same bowl, add mayonnaise, Dijon mustard, and apple cider vinegar. Mix until well combined and adjust seasoning with salt and pepper.

Gently fold in the cooled potatoes, ensuring they are evenly coated without mashing.

Cover with plastic wrap and chill in the refrigerator for at least one hour before serving.