That is all....
I want to thank Cannonman for showing me the ways. Went from 3 kills total to halfway to mastery in a night.
Basically you take their shields down with a plasma pistol or AR burst and then throw one at their feet. The inital explosion does lethal damage to unshielded enemies in blast radius.
So far I've gotten a few double kills, a scorpion kill, and a pulse grenade yoink.