Three steps that come to mind (there might be others but this will get you started):
Remove the .app from the /Applications directory.
Remove any references from the LocalizedApplicationNames.strings file (would be two lines for each application, make sure you get analyze the pattern, so you don't remove the wrong lines!)
Remove any references from the DisplayOrder.plist file (also two lines for each application, make sure you get analyze the pattern so you don't remove the wrong lines!)
