Preheat fryer to 400°. Peel & cut potatoes lengthwise in 1/2” slices; & in 1/2” sticks. In bowl, toss potatoes w/oil, pepper & salt. In batches, place in single layer in fryer basket; cook 5-10 min. Toss; cook until lightly browned & crisp, 5-10 min. Bowl #1, mix flour & pepper. Bowl #2, whisk egg w/water. Bowl #3, toss cornflakes w/cheese & cayenne. Sprinkle w/salt; dip fish into flour to coat; shake off excess. Dip in egg, then cornflakes, pat to adhere. Remove fries from basket. Place fish in single layer in fryer. Cook until lightly browned & flaky, turning once, 8-10 min.