The Technomancer

This achievement is very easily gained during the tutorial level. All the Mantis creatures you see in the Old Dome count towards this achievement, so kill all of them. When facing the boss, it will also spawn extra Mantis.

Draining creatures does not effect your karma, so you should drain them after you knock them out for the "kill", as the achievement states.

If you didn't get it, there's two other notable places that are good for hunting:
1. The Underworks in Ophir - Available in all chapters but 4. You will mostly see Mole Rats and the Alligator creatures, both of which are easier prey.
2. The Shadow Path - Noctis - Available after chapter 1, and lost at 4. The Ostriches and other creatures are much more dangerous, but the achievement can still be done.

All creatures respawn in areas, so there's little reason to miss this achievement. Don't forget to invest in Exploration so you can skin the animals. This is required for a different achievement (Trapper).