Boil the Potatoes: Place the diced potatoes in a large pot and cover them with cold water. Add a pinch of salt. Bring the water to a boil over high heat. Reduce the heat to medium and let the potatoes simmer for about 10-15 minutes, or until they are tender and easily pierced with a fork. Drain the potatoes and let them cool completely.

Prepare the Dressing: In a large bowl, combine the mayonnaise, Dijon mustard, apple cider vinegar, salt, and black pepper. Mix well until the dressing is smooth and creamy.

Mix the Ingredients: Add the cooled potatoes, chopped red onion, chopped celery, chopped hard-boiled eggs (if using), chopped dill (if using), and chopped parsley (if using) to the bowl with the dressing. Gently stir until all the ingredients are evenly coated with the dressing.

Chill the Salad: Cover the bowl and refrigerate the potato salad for at least 1 hour, or until chilled. This step allows the flavors to meld together and enhances the overall taste.

Garnish and Serve: Before serving, give the potato salad a gentle stir. Garnish with a sprinkle of paprika (if using) for added color and flavor. Serve chilled.