I did point out many people to the Google Chrome extension manager but you can still uninstall extensions in Chrome without having to use a additional tool.
Here are some of your questions answered with regards to using extensions in Google Chrome.
Where Are Google Chrome Extensions Installed?
Google Chrome installs all extensions into the user profile, you can find it under the default installation folder. Once you are inside the installation directory, go to User Data folder and then to your profile directory, if you don’t have any profiles it will be the Default folder.
You will find all the extensions inside the Extensions folder inside your profile folder, deleting will delete the extension.
Uninstall Extensions in Google Chrome
To uninstall extensions in Google Chrome follow the steps listed below.
Step 1: Open a new tab in Chrome and type in chrome://extensions/without the quotes in the Omnibar, this should open the inbuilt extension manager in Chrome.
Step 2: On this page you will find options to uninstall extensions that are installed for your profile, click on the Uninstall button to remove the extension you want to.
As easy as it gets once you know where to look :-), hope this helps you out.