Boil potatoes until tender, about 20 minutes. Do not overcook or they will get mushy.
Drain potatoes from water, and rinse with cold water and let cool slightly.
Cube the boiled potatoes into bite sized pieces.
Add the cubed potatoes to a large mixing bowl. Add in celery, chopped herbs and the white part of the green onion. Mix well.
In a small bowl, add together the dressing ingredients and whisk until combined.
Drizzle the dressing over the potatoes and stir to mix. Top with the chopped green part of the green onion. Chill until ready to serve.