Peel the potatoes, and cut them lengthwise into strips 1/4-inch thick. In a bowl cover the potatoes with cold water and let them soak, chilled, overnight.
In a deep fryer or heavy saucepan preheat the oil to 325 F-. Drain the potatoes and pat them dry. Sprinkle the potatoes with cornstarch shaking off the excess. Add the potatoes to the oil and fry them for 3 to 5 minutes, or until they are soft and just beginning to brown. With a spider or slotted spoon transfer the potatoes to a tray lined with paper towels to drain.
Just before serving heat the oil in the deep fryer to 395 degrees. Add the potatoes and cook for 1 minute, or until golden. Transfer to paper towels to drain, sprinkle with salt and serve.