Removing all of an Application?
This is very tricky. From 10.6.6 (when Apple released the Mac App Store), the App Store has been pretty deeply built in to the system. You can see this by the fact that if you click on the  in your Menu Bar, there is an option to launch the App Store from there.

In later versions of OS X it is even more deeply embedded as software updates for the OS are downloaded through the App Store. In order to completely remove all trace of the App Store and still have a stable system that won't crash or kernel panic, you would have to dig in to some of the Apple Frameworks and binaries to remove references for the App Store.