THE PERFECT HAIRCARE Microfiber Hair Plopping Towel Set – Super Absorbent Anti-Frizz Hair Drying Wrap + 2 Curl Scrunching Towels – Fast Drying, Lightweight Wrap for Women, Girls & All Hair Types

You mught be able to get away with The Perfect Haircare Towel. It's paper thin and resists sand. I know it's for hair, but it's pretty big. If I hold it up at shoulder level is goes to the middle of my shins. It folds up to washcloth size. I think they might have an XL size also. Edit: and it dries super fast!