Add the potatoes to a large pot and cover with water. Add kosher salt and bring to a boil, cover with a lid and cook the potatoes until soft, about 30 minutes.
Remove the potatoes from water and let cool. Once the potatoes are cool, cut into ¼-inch pieces.
Add the celery, shallot, pickles, green onion, rosemary, and thyme and stir. Fold in the mayonnaise and mustard.
Season to taste and stir again. Serve cold.