Italian Tuna Melt with Provolone and Arugula

thin slices Red onion

Tight-packed arugula

Mayonnaise, light

White balsamic vinegar

Salt

Olive oil, extra virgin

Prime fillet albacore tuna with sundried tomatoes and olive oil

slices Provolone cheese

(5 inch x 5 inch) ciabatta sandwich roll (if not available, purchase a full loaf and cut portions)