For easier clean-up, cover the baking sheets with aluminum foil first, then coat the foil with cooking spray. You can do this by cutting the potatoes in half lengthwise, in half again, and then into wedges, and finally into thin strips.  The matchstick shape is important. Combined with the high baking temperature, it is what will give you nice, crispy fries. You can leave the potatoes unpeeled, or you can peel them first. Consider adding other seasonings, such as pepper, garlic powder, and fresh, chopped rosemary. You will be tossing the potatoes in this, so make sure that the bowl is big enough. An easy way to do this would be to cover the bowl with a tight-fitting lid, and then shaking it. Make sure that the fries aren't clumped together or touching. Use another baking sheet, if necessary. If the fries are clumped together, they won't turn out very crispy. The longer you bake them for, the crispier they will become. About halfway through the baking time, toss the fries with a spatula or a pair of tongs. This ensures even baking. To make garlic fries: During the last 10 minutes of baking, sauté 3 cloves of garlic in 1 to 2 tablespoons of olive oil until it turns brown, then set it aside. Use a spatula to transfer the fries from the baking sheet to your serving dish. If you are making garlic fries: season the fries with sea salt, then drizzle the sautéed garlic over them.
Preheat your oven to 450°F (233°C) and generously grease a baking sheet with cooking spray. Cut the potatoes into ¼-inch (0.64-centimeter) thick matchsticks. Mix together the oil and salt in a large mixing bowl. Toss the potatoes with the oil and salt. Spread the potatoes out in an even layer on the greased baking sheet. Bake the fries for 25 to 35 minutes. Season the fries, if desired, then serve them immediately.