Place potatoes into a large bowl. Drizzle with olive oil and add salt, pepper and red pepper flakes. Combine until well coated.
Put the potatoes directly on the grill and close grill top. Turn potatoes onto the other side after 3 to 5 minutes. When ready, place back into the bowl and add the onions and bacon. Drizzle potatoes with dressing, toss and serve garnished with chives.