EDIT: Never mind, I catch your meaning now.
Does iKill have docs somewhere?
Not AFAIK, but from a users viewpoint the operation is fairly simple, I think the "i" in the name stands for intuition, so getting rid of intuition windows + related tasks is pretty much what it does. The single argument you can give it on the command line is a taskname, you can use the TaskList command to see current task states. There is no safe way to reclaim resources from dead tasks, so once you've saved whatever you're working on you should probably consider rebooting.