Yeah, that doesn't exist any more and we have to configure compiz manually from what I know. May be they removed it because of problems that may arise with configuring unity that way, I am not sure why.
Since you are on 12.04 or later, and I am assuming that you have compiz installed, if not use
sudo apt-get install compizconfig-settings-manager
to install it.
From there on you can configure it in different ways as you like. Here are more places where you can read some material/guides on cool tweaks you can do with this tool once you install it.
How to change color of unity workspace border, and window resize
If you find some feature name not understandable, take a look at compiz wiki and read what that feature does, and then tweak it if you want to. Happy tweaking!