Heat oven to 425°F.
Peel sweet potatoes and slice into 1/4-inch classic fry sticks, about 3–4 inches long.
Pat the cut fries dry with paper towels and place them in a large bowl.
Add avocado oil, paprika, garlic powder, and onion powder, then toss until the fries are coated.
Line a rimmed sheet pan with parchment paper and spread the fries in a single layer with space between each piece.
Bake for 15 minutes, flip with a spatula, then bake 12 more minutes.
Set the oven to broil and broil for 1 minute to crisp the edges, watching closely.
Remove the pan and sprinkle the fries with flaky sea salt.
Stir the mayonnaise, hot sauce, lime juice, fine sea salt, black pepper, and optional paprika or garlic powder in a small bowl until smooth.
Serve the hot fries with the spicy mayo for dipping.
To reheat leftovers, bake at 425°F until crisp again.