Place the potatoes in a large pot, add the water and the 1 tbsp kosher salt (for boiling water), and bring to a gentle boil over medium-high heat; simmer until just tender when pierced, 15β20 minutes. Drain, let steam-dry 5 minutes, then peel while warm, cut into 0.25-inch slices, and place in a large mixing bowl.
Cook the bacon in a large skillet over medium heat until crisp, 8β10 minutes; transfer to the bowl with the slices and leave about 3 tbsp drippings in the skillet.
Add the onion to the skillet and cook in the drippings until translucent and lightly golden, 3β5 minutes; stir in the sugar and mustard and cook 30 seconds to bloom.
Pour in the vinegar and broth, scraping up any browned bits; simmer 2β3 minutes, then season with the black pepper and the 0.5 tsp kosher salt (for seasoning); remove from the heat.
Pour the hot dressing over the bowl; gently fold to coat and let stand 10β15 minutes, stirring once or twice, until the liquid is mostly absorbed and the slices are well glazed.