At the very first area of the Archer's Pass, where the first save spot is, under it you will see a bomb fruit. Flying enemies will fly around chasing you. Gather a bunch of them from the right side of the save spot, lure them to the save spot, stand there making sure there's at least 6 enemies there, press Y button to start your Dust Storm attack while standing on flat surface. You will pull the bomb fruit close to you and 6 or more enemies will blow up! This is one the earliest and easy ways to get this achievement.