1. Start a level
2. Turn off your controller
3. Wait till your friend is right near end of the level with no lives lost
4. Turn the controller on
5. You have aced a level without doing anything
I have also done this months ago....the problem with this method is that you need to find a friend who would willingly ace all levels and wait for u to join him at the end.
If you dont have someone like that, you may as well pay someone else to do the acing, if you cant do it yourself.