In a medium non-stick skillet, heat the olive oil to approximately 300-325 degrees Fahrenheit. Add the potato and onions to the hot oil alternately, in layers. (The oil should be hot enough that the potatoes will begin to bubble immediately, but not so hot as they will brown; the potatoes are being somewhat poached in the oil, rather than fried.) Cook the potatoes and onion, over medium heat for approximately 5 minutes, just until the potatoes are beginning to soften and the onion is translucent. Drain the potatoes and onion through a colander, reserve the oil and allow the vegetables to cool somewhat. Beat the eggs with the salt and pepper and add the cooked potatoes and onion to the egg. Gently fold and mix the potato and onion with the egg until everything is thoroughly coated. Heat 1 tablespoon of the reserved oil, over medium-high heat, in the same non-stick skillet. (The remaining reserved oil can be kept refrigerated for future use; the onions and potato impart a delicious flavor into the oil.) Add the omelet mixture to the skillet and gently press down on the potatoes to form a cake. When the tortilla begins to become firm, it should be flipped; this can be in a variety of ways. If you feel comfortable, flipping it free-hand is most desirable. Otherwise, you can slide it onto a clean plate and invert the plate onto the hot skillet, or you may simply attempt this feat with an ordinary spatula. Turn the tortilla a few times (it gets easier) to complete the cooking process. When the tortilla is cooked, remove it to a clean plate. This omelet can be eaten hot, but the textures and flavors improve if left to stand for a few minutes and cool to room temperature.