Wash the potatoes well. Cut the potatoes in half, leave the skin on, and place them in a stock pot. Fill the pot with water, covering the potatoes completely. Add a big pinch of salt and bring to a boil. Simmer for 15-20 minutes or until fork tender.
Drain the potatoes and set aside.
Make the vinegar dressing
In a medium-sized mixing bowl, combine all the ingredients for the dressing and whisk until well combined. Place the slightly cooled potatoes into the dressing and toss to combine.
Add the spring onions and chives to the potatoes and toss once more. Chill before serving. Best enjoyed within 3 days.