Removing the Proctorio extension from Google Chrome is very easy. So easy in fact that if leaving it installed causes concern, you can actually install it before each exam you need to take and then remove it right afterwards.
See below for a quick video or instructions about how to remove the extension so that Proctorio no longer has access to your system:
Proctorio should now be removed!
If you must take another test using the Proctorio extension, note that you will need to install it again. However, you can install and uninstall it as many times as you wish.