In a 12-inch skillet over medium heat, heat the oil and in it cook the potatoes and onion until the potatoes are tender, 8-10 minutes, stirring frequently.

In a medium bowl, beat the eggs, cream cheese and salt. Pour over the potato mixture in the skillet. Reduce heat to medium-low, stirring lightly until the mixture is set, about 5 minutes.

To serve, cut the tortilla into wedges. Serve hot or refrigerate to serve later