Spiralize the potatoes using the thick setting on your spiralizer. (If you don't have a spiralizer, julienne slice the potatoes with a kitchen knife.)
Heat 2 Tbsp oil in skillet and add chopped onions. Saute until soft but not too browned.
Add yellow mustard to the onions and saute for another minute.
Add Thousand Island dressing to the mix and saute for another minute. Turn heat off and set aside until potatoes are fried.
Heat 2 cups of oil in a skillet until shimmering. Make sure oil is very hot or the potatoes will stick to the bottom of the pan.
Add potatoes in batches, not over-crowding them so that they move about freely in the skillet.
Once the potatoes are browned, remove from oil and set on a paper-towel lined plate or screen to drain.
Once potatoes are fried, plate them and spoon the onion/Thousand Island mixture over the top. Sprinkle with fresh ground black pepper and grated cheddar cheese if you like that.
Put on a bib and enjoy every single crunchy, gooey bite.