This achievement is most easily earned with two Ion Blast II cannons and perhaps an Ion Bomb. After ensuring that the shields will remain down long enough, simply changing the targets temporarily to other sytems should be enough to have four ionized at once, especially if a veteran gunner is manning the weapons.
Oddly enough, this achievement can be grabbed easily by visiting a Pulsar and letting it do most of the work for you. Systems that have cooldown periods such as cloaking, hacking and teleporters also count towards this achievement. For instance, when fighting an enemy ship that uses mind control, a teleporter and a cloak, you can earn this achievement simply by ionising their shields while their other systems are recharging.
This achievement is a reference to Episode IV of Star Wars, the phrase is mentioned by a squad member after the Death Star's turrets stop firing to allow Imperial fighters to ambush them.