Tunnelblick does not appear in the "Force Quit" list.
If Tunnelblick hangs (which is what you have described), you can force it to quit using OS X's "Activity Monitor" program:
- Launch "Activity Monitor" using Spotlight. (Or launch it manually – it is in the "Utilities" subfolder of the "Applications" folder.)
- Look for a process named "Tunnelblick" in the list of processes and click on it so it is selected. (The entire line with "Tunnelblick" will be highlighted.)
- Click the button with an "X" in the top left corner of the Activity Monitor window. A small window will pop up.
- Click the "Quit" button in that small window. Tunnelblick should quit and the window will disappear. (See the Note below if Tunnelblick doesn't quit.)
- Click on the "View" menu, then click "All processes".
- Look for all processes named "openvpn" and for each one, select it, click the "X" button, and then click the "Quit" button in the small window that appears.
Note: If Tunnelblick does not quit in step 4, repeat steps 2 and 3, but then click the "Force Quit" button in the small window that pops up. (Do that only if absolutely necessary.) Similarly, if an "openvpn" process does not quit in step 5, click on the "Force Quit" button. You may be asked for your password to "Force Quit". (You must enter the username and password of an administrator if you are a standard user.)
As FishingAddict pointed out, you can uninstall Tunnelblick by using the instructions at https://tunnelblick.net/cUninstall.html. Do not just drag Tunnelblick to the Trash; that will not completely uninstall it.
However, if you want to uninstall it because of this "hang" problem, that problem is fixed in Tunnelblick 3.6beta18, which you can download from the official Tunnelblick Download page (https://tunnelblick.net/downloads.html). It is a good idea to "verify" the download using the instructions on that page.
Tunnelblick betas usually work very reliably and fix problems that have not been fixed in the "stable" versions. Tens of thousands of people use the "beta" versions.