Adding the Print Document Option To The Right-Click Contextual Menu?
As suggested on this blog, you can use the following applescript : 

tell application "Your Printer Name Here"
   activate
   print theFile without print dialog
   quit
end tell


To add it to the contextual menu, do as usual : Create a new automator service with this script. 

Don't forget to select Service receives selected file and folders in the app you want (At least Finder but it can be from any app).