KYLIE JENNER HER ASS IS ON VACAY ... Tyga's Hands Working watch

When Kylie Jenner goes on vacation ... Tyga wins big time. So do we, come to think of it.

KJ and Tyga are down at Joe Francis' famed estate in Punta Mita, Mexico ... and lounging by the pool. Kylie didn't leave much to the imagination Tuesday as she flaunted some ass-tastic swimwear.

:Two things
1. She's gonna need more sunscreen

2. Tyga's hands never looked so small