I want to kill some liquid particle in a certain area of the sim… is this possible?
Yup - Clear Inside in the right click props 
You can choose which particle or grid channel you can kill too.
Inside the right click properties of any object? so I can just place it in the scene and turn that object into a deleter?
That’s right! Just make sure to set it to Non-Solid if you don’t want it to interact with the rest of the simulation.