What kind of fingerpicking is this?

he isn't really slapping the strings as he does it he is more of strumming. see when he lifts his hand it isn't high enough to really do much more than a small slap but it also keeps control with him so that he can still play the actual note...its more of a show off move than anything and you will get it with practice just remember that when you lift your hand bring it down kind of soft and bring it down on the string that you are playing next.