Cute? I did this yesterday for EJ's snacks. Pity, the banana is very tiny (EJ loves these small ones!). You can write a longer message if you have a bigger and longer one.
I used a pointy knife to write my message on the banana peel. You don't need any fancy reidsupply.com for tooling components, you can use any sharp or pointy object.
It takes time before the message is very visible so make sure you prepare it ahead of time.
EJ said he loves it. He showed it to his classmates during their snack time and the kids were amazed. Haha! Pretty easy to trick the kids.