You can most likely get this as you progress through "The Foundation" DLC. But I found myself a few short upon completion, so I went to the Control Point at Maintenance > NSC Power Plant.
This area is usually populated with low-level enemies that can be killed with one hit of "Shield Rush 1", there's usually a dozen or so enemies here. Kill the enemies, travel to another Control Point and travel back to NSC Power Planet and repeat until the achievement unlocks.
Tip from: Wriggy