This must be done through out the single player campaign.
While playing the game you will notice that In the lower left hand corner of the screen is a meter in the shape of the D-Pad. Every kill and paper crane you get adds to this meter.
The Barrage special move is on the right side of this meter. When the bar passes the right side (going clockwise) hit right on your D-pad you will activate the barrage special move.
While in this limited time effect get as many kills as possible. Every kill you get counts towards this achievement. Basically just keep using the barrage special move when you can and get as many kills as you can. As soon as you get your 100th kill using the Barrage special move you will unlock this achievement.