This achievement can be obtained by buying the Shuriken holster 1 from the battle item shop on the bottom left of the map for 5000 RYO to which I then suggest finding 5 targets which items can be thrown at then press
to get into aiming mode then hold
and move around
so that the 5 targets have the crosshairs on them then release
and you will fire the 5 sets of Shurikens allowing for the achievement to be obtained