Paper fingers is merely a quirky name for a small piece of folded-over card or stiff paper that you use instead of your fingers to pick up things. It's an easy way to pick up a painting or sheet of paper without accidentally getting paint from your "real fingers" on it.
Paper fingers work best with a bit of card of paper that's stiff enough to have a little spring in it. That way it stays open when not in use and is easy to slide under the edge of whatever you wish to pick up.
