I'm looking for any existing touch gestures that mean "create new" (e.g. "create new document", "create new graph", "create new tweet", etc). Can anyone cite any existing "create new" gestures?
Gestures that don't mimic real physical interaction are not easily learned. I would suggest you do not use a gesture for this but a button, icon, or text instead.
Questions to ask before introducing a gesture:
Am I adding value? Or is it a gimmick?
Does this gesture make sense if it were manipulating the physical.
How many seconds does this add to the users goal? Both in action and in learning.