I am Unable to Uninstall an Applications like Node or Atom in OS X I just bought a Macbook Pro and I'm new to OSX. I can't uninstall applications like Node, Atom, etc. They are not shown in my Application folder  nor in the Launcher.  How can i delete them?'

Below is screenshot of my Applications folder.  However, if I search for Atom using Spotlight,  I can access it from there.
Have you tried emptying your trash? Spotlight can find and open (IIRC) applications that remain in trash.

If after your trash is emptied and you still see Atom or Node, try, in Terminal:

sudo find / -iname 'thing'


in which you should substitute thing with your search query.

EDIT: in Spotlight, when you hold Command, does it show a path at the bottom of the spotlight window?

EDIT 2: As per @Lizzan's comment, do check your Downloads, Documents, and any other user-related folders.