Mix mayonnaise, parsley, lemon juice and peel in a small bowl.
Mix salt, pepper, cumin, paprika and red pepper in a shallow
bowl. Add chicken cutlets to spice mixture; turn to coat, then
brush both sides with melted butter. Place in a single layer
on wax paper.
Heat a well-seasoned large cast iron skillet over medium-high
heat just to smoking. Add half the cutlets and sauté
just til cooked through, 1 1/2 to 2 1/2 minutes per side.
Transfer to a plate and cover to keep warm. Repeat with
remaining cutlets.
Spread 1 tablespoon lemon mayonnaise over each slice of bread.
second slice of bread. Serve with potato salad.