Place the potatoes into a large pot, cover potatoes with water and season generously with salt. Bring water to a boil and cook until potatoes are easily pierced with a knife, 15 to 20 minutes. Drain and transfer to a large bowl.
Meanwhile cook bacon in a non-stick skillet over medium-high heat until crisp (about 6 – 7 minutes). Remove bacon, set aside and leave drippings in skillet.
Add onion, green onions and garlic to the bacon grease, and cook over medium heat until soft and transparent (about 3 minutes). Add the vinegar, black pepper, and olive oil, sugar and Dijon mustard to the pan and bring to a boil. Pour mixture over the potatoes add parsley and bacon, and mix well. Taste and adjust pepper and salt if necessary. Mix again and transfer to a serving bowl. Serve warm.
