Fill a Dutch oven halfway with peanut oil and preheat to 350 degrees F.
Mix together the salt, smoked paprika and chili powder in a small bowl.
Using a mandolin (with the waffle blade if you have it!), slice the potatoes thinly, dropping them into a bowl of cold water as you go. Remove the potatoes from the water and blot dry with paper towels.
In batches, fry the potatoes until golden brown, 2 to 5 minutes. Drain on a paper-towel-lined baking sheet and season with the spice mixture.