Yes. Leftover slices of flank steak make the BEST steak sandwiches ever. You can also use them to top a salad or in a pita pocket with some sprouts. If you have enough to eat as an entree again, warm it up slowly in a 200ºF oven for 20 minutes to preserve some of the pink in the middle. Store leftover grilled marinated flank steak in an air-tight container for up to 5 days.