Preheat the oven to 450 degrees F.
Cut the potatoes lengthwise into 1/4-inch thick matchsticks, and toss with the oil and 1/2 teaspoon salt. Spray a baking sheet with cooking spray. Arrange the potatoes in a single layer on the baking sheet and bake until the "fries" are tender and crisp, about 30 minutes.
Season with additional salt, to taste. Serve immediately.