In a large skillet, heat 2 tablespoons of olive oil, then add potatoes & salt.
Fry, stirring occasionally, perhaps about 5 minutes, until potatoes are a golden color, then remove from the skillet & spread out on a paper-towel covered platter so that much of the oil can be removed.
In a large bowl, whisk eggs well, then to them add the potatoes, mixing well.
Using the same skillet as before, cover the bottom of the pan with a thin layer of oil, about 1-2 tablespoons.
Once the oil is hot, add potato & egg mixture, shaking the pan gently as you move the mixture, so that none sticks to the bottom.
Once omelet seems to be cooked, about 10 minutes, use a large plate to tip the omelet out of the skillet. After adding a little more oil to the skillet, slide the omelet in again, this time putting it in top-side down & cooking it until the under-side is also golden.