In levels with winding pathways in which lines of balls criss-cross each other, it's possible to create a gap by making a match or two. Once this happens, you have a window of opportunity (sometimes brief, sometimes longer) to fire a shot through the gap and make a match. Do so and you'll get not only a score bonus, but also the Achievement.
I got this on level 1-5, but you can actually get it as early as 1-1. Just wait until the curve wraps around the lower section and has doubled back on itself. Then blast a hole in the closer part of the curve and fire through that hole to make a match, and achievement unlocked!
eastx Credits: Ben Ahroni at PopCap for the tip!