Login to admin.google.com as an administrator

On the left hand side click Devices

Then click Chrome

Then click Apps & extensions

Then click Users & browsers

On the left under the Apps & Extensions text select the Group(s) or Organizational Unit(s) that it was previously installed on

On the right hand side you should see the app in the list. It will be named npnkndcccppmijoadmlaacmfbolcfppp and have a dark gray square icon with lighter gray dots in it.

Click the row that the app is listed in and then a new pullout menu will appear on the right hand side.

At the top of this menu there will be an option that should be set to Force Install or Force Install + Pin, click this drop down and change it to any of the following to uninstall the extension: Allow Install, Block

Alternatively you can click the trashcan icon at the top and then select DELETE in the popup window. This will also remove it from the list of apps that you have.

Repeat steps 6-10 for each OU/Group that you had installed the extension on.

Generally we see the extensions being immediately removed from the computers, but Google states it can take a few hours before they are uninstalled.

Another thing to note is that any computer that is not connected to the internet will not have the extension uninstalled until they reconnect to the internet.