Cook the potatoes in simmering salted water until just tender, about 15-18 minutes. Drain and dry. While the potatoes are still hot, remove the skins and slice the potatoes 1/2-inch thick.
While the potatoes are cooking, prepare the dressing. Cook the bacon over medium-high heat until the fat has rendered and the bacon is crisp. Remove the bacon to a plate with a slotted spoon, reserving the bacon fat in the pan; crumble the bacon into small pieces, and reserve.
Bring the chicken broth, vinegar, onions, salt, sugar, and pepper to a boil.
Combine the oil, rendered bacon fat, and mustard with the warm potatoes. Pour the boiling broth-vinegar mixture over the potatoes. Toss in the crumbled bacon and chives.