- Position racks in the upper and lower thirds of the oven and preheat to 450 using the convection setting, if available.
- Place a baking sheet on one of the racks to preheat.
- Prepare the chips: cut the potatoes into ¼" thick sticks.
- Toss with the olive oil and cayenne in a bowl.
- Carefully remove the hot baking sheet from the oven, add the potatoes and spread in an even layer.
- Use a rubber spatula to scrape any oil from the bowl over the potatoes.
- Bake on the top oven rack, turning once, until browned and crisp, 25 to 30 minutes.
- Season with salt.
- Meanwhile, make the fish: set a wire rack on a baking sheet and coat with cooking spray.
- Lightly crush the cereal in a bowl with your fingers.
- Add 2 teaspoons salt, and black pepper to taste.
- In another bowl, whisk the egg whites and a pinch of salt until frothy.
- Dip the fish in the egg whites, then roll in the cereal crumbs to coat.
- Place the fish pieces on the rack (position them on their sides so that the majority of the crust is exposed) and mist with cooking spray.
- Bake the fish on the bottom rack until crisp and just cooked through, about 12 minutes.
- Season with salt and pepper.