Rinsing the kite will shorten its life IMO.
It will definitely shorten YOUR life, all that waste of time used doing this...
You fold and unfold the kite the double amount and put a lot more wear on the kite, and if there is ANY slight damp left, mildew will ruin your kites, it can happen overnight sometimes...
I ride about every second day in average - one, and sometimes two kites each time, so that is another reason NOT to wash the kites, as then they could not get dry before the next day ha haa
Always ride in saltwater, but never leave them wet though, so if it occasionally gets in the drink and no more wind, or the very rare days when it starts to rain, I dry the kite before the next day (not rinsing, way too much risk with fresh water)
Peter