Put the potatoes in a pan of water and and cook until tender, i.e until you can easily insert a fork.
Drain, let cool to lukewarm, peel and slice.
Heat the oil in a pan over medium heat and add the finely chopped onion.
As soon as the onion begins to brown, add the cubed bacon or pancetta and the potatoes, stirring well to keep them from sticking to the pan.
After 3 or 4 minutes, add the eggs beaten with a pinch of salt and hot peppers.
Stir vigorously with a wooden spoon, and once the omelet begins to come together use a spatula and a plate, if necessary, to flip it over and cook on the opposite side for 5 minutes (all of the above must be done over high heat so the omelet browns on the outside but remains soft on the inside and is not too greasy).