Heat gun to soften the vinyl and a plastic scraper with a sharp edge should do the trick.
Apply heat to the character, just enough that you can get a corner lifted then while still gently heating try to pull it off as one piece.
John. Duct tape is like "the Force", it has a dark side, it has a light side and it holds the universe together. nothing screams poor workmanship more than wrinkles in Duct tape.