Seriously, though...how would you even do that? Use the Force?
"Sorry, ma'am...I am not a Jedi. Yet."
What could that lady have possibly expected you to do? Maybe some sort of inner-wrap scenario, where, instead of touching the
foil, you grab the sandwich itself - using it as some sort of bread-based glove - and grab the foil that way, with the sandwich acting as a hand barrier, and just roll it into some sort of ball until it looks "wrapped"?
Or just ask. I'd be curious to hear her answer.
"Can you help me out here and tell me exactly how I should go about that? No, really...I'd like to know! Because this
isn't a magic-tricks-while-u-wait kinda joint. Shall I try to levitate the mustard and turn the cash register into a tiger while I'm at it?"