Place the diced potatoes in a large stockpot and add enough water so that the potatoes are covered by 1 inch. Cook over medium-high heat until the water reaches a boil. Then reduce heat to medium to maintain the simmer, and continue cooking the potatoes for 5-8 minutes or until the potatoes pierce easily with a fork.
Drain the potatoes in a colander. Then return the potatoes to the stockpot, drizzle evenly with the vinegar, and let the potatoes rest for 20-30 minutes or until cool enough to handle.
Meanwhile, whisk together the mayo, celery salt, mustard in a medium bowl until evenly combined.
Once the potatoes are ready to go, add in the mayo mixture, diced eggs, celery and onion. Toss gently until evenly combined.
Taste and season with salt and pepper, to taste. (Also feel free to add in a tablespoon or two of pickle juice if you would like.)
Transfer the potato salad to a serving bowl, cover, and refrigerate for 1-2 hours to chill.
Serve chilled, or refrigerate in a sealed container for up to 3 days.