Cut the red potatoes into 1-inch chunks and place them in a large pot of cold salted water. Bring to a boil and cook for 12-15 minutes until fork-tender but still holding their shape. While the potatoes cook, finely dice the red onion, celery, and dill pickles into uniform sizes—this ensures even distribution of flavors throughout the salad. Mince the fresh chives and fresh dill and set aside. Drain the cooked potatoes in a colander and spread them on a plate to cool slightly while you continue prep work; I prefer to dress the potatoes while they're still slightly warm so they absorb the flavors better.
In a large mixing bowl, combine the sour cream, mayonnaise, and Dijon mustard, whisking until smooth and fully incorporated. Add the pickle brine to the mixture and stir to combine—the brine adds brightness and reinforces the pickle flavor throughout the salad. This creates your creamy base that will coat all the ingredients evenly.
Chop the 4 large hard-boiled eggs into bite-sized pieces, being careful not to mash them into powder. Set aside to add at the end, which keeps them from breaking down into the dressing and maintains their texture in the finished salad.
Add the cooled potatoes from Step 1 to the creamy dressing base from Step 2, along with the diced onion, celery, and pickles. Fold gently but thoroughly to coat all the potatoes evenly. Add the chopped eggs from Step 3 and the minced chives, folding gently to combine while preserving the egg pieces. I find that folding rather than stirring vigorously keeps the potatoes and eggs intact and creates a more appealing texture.
Sprinkle the sea salt, freshly cracked black pepper, celery seed, garlic powder, smoked paprika, and the fresh dill over the salad. Fold gently to distribute the seasonings evenly throughout. Taste and adjust salt and pepper as needed—remember that the pickles and pickle brine already contribute significant salt, so taste before adding more.
Cover the salad and refrigerate for at least 30 minutes before serving, which allows the flavors to meld and develop. The salad can be made up to 4 hours ahead of time. Give it a gentle stir before serving to redistribute any dressing that has settled at the bottom.