Wing Surfing is typically a step in learning to Wing Foil, but not necessarily. Winging is all about having fun regardless of what you are standing on!
Learning on a larger board that supports your weight in the water makes learning to use the wing much easier. Do you have a Stand up Paddleboard (SUP) that's not being used all that often? Dust that beautiful board off, add a SUPWinder, grab a wing and Voila.. you're now Wing Surfing!