Heat oil in a medium non-stick skillet over high heat. Add potatoes (in batches if necessary). Reduce heat to medium-low and allow potatoes to cook until tender. Note that the goal is not to brown the potatoes, but rather to cook them slowly until tender.

While potatoes are cooking, whisk eggs and water in large bowl.

Once potatoes are tender, remove from skillet with slotted spoon and transfer to bowl with egg/water mixture.

Pour egg/potato mixture into skillet, reduce heat to low, salt to taste, and cook until egg is almost set in the center. Flip and cook on other side until firm, being careful not to burn egg.

Cut tomatoes in half. Taking the cut side, grate tomatoes over a bowl until you are left with just the skin which can be tossed. Add salt to taste.

Spoon tomato salsa over Tortilla de Patata just before serving. Enjoy!