How to remove an application that has been deleted but remains in the Status bar?
From Citrix.com - How to Uninstall Citrix Online Plug-in For Mac

This is the instructions for Online rather than Receiver. The process is identical for each, substituting the Receiver .dmg file
(the Receiver instructions are in a pdf rather than online &amp; can't be copy/pasted)


  Citrix Online Plug-in (client) for Mac installs files into multiple
  folders. Here is an easy way to uninstall:
  
  Download the installer from Citrix download page. 
  
  Open the file and select Uninstall option.