Use clear packing tape. If you read the tape labels, you might be able to determine how thick the tape is, you want the lightest, thinnest stuff you can get your hands on, no "heavy duty" anything here.

Btw, if you're worried about folding the wing, you can run a strip of tape on the underside of the wing. Pull the tape so it's under a little tension when you put it on. Now, for the wing to fold the tape will have to break or slip, and it won't do either.