From torproject
How do I uninstall Tor? Tor Browser does not install itself in the classic sense of applications. You just simply delete the folder or directory named "Tor Browser" and it is removed from your system. If this is not related to Tor Browser, uninstallation depends entirely on how you installed it and which operating system you have. If you installed a package, then hopefully your package has a way to uninstall itself. The Windows packages include uninstallers. For Mac OS X, follow the uninstall directions. If you installed by source, I'm afraid there is no easy uninstall method. But on the bright side, by default it only installs into /usr/local/ and it should be pretty easy to notice things there.
That left me a little confused.
Yes. When a file is deleted, the space it takes up on the disk is marked as unused, but the data that makes up the file is not erased and could be recovered with a disk forensics tool.
Try this method to wipe the free space on your disk:
http://www.pcmag.com/slideshow_viewer/0,3253,l=255105&a=255105&po=8,00.asp
Also see this:
https://www.piriform.com/docs/ccleaner/using-ccleaner/wiping-free-disk-space
https://www.piriform.com/ccleaner