Preheat the oven 365F. Cut the potatoes and arrange on a baking sheet, drizzle with olive oil, sprinkle with salt and pepper. Roast until the skin are golden.
To make the dressing: blend aquafaba, vinegar, grape seed oil, cane sugar, salt, and dijon mustard using immersion blender for 3-5 minutes. Add parsley, green onions, garlic and process until smooth. Season to taste with salt and pepper.
To serve, put the potatoes in a serving bowl, add the dressing, and toss to coat.