Activate Application Window on clicking dock icon I would simply like to activate Application Window when clicking on the dock icon.
Currently you must hold the icon to activate the functionality I would it to automatically occur just like Ubuntu's when making the 2nd click.

Please refer me to a different site if this should be posted elsewhere.
No, there is not. Expose is built in to the core of OS X. You cannot replace it, but you can turn it off in the System Preferences. As far as I know there is no third party Expose for OS X. 

Ubuntu is probably using a similar version of expose used in earlier versions of OS X. Most operating systems implemented such a thing a few years after the first time OS X was published with that functionality. It changed over the years (and is now mostly taken over by Mission Control), but the ones used in other operating systems might not have taken the same path.