Mr.Klingon's fast intro to speaking tlhIngan Hol! (the Klingon Language)
Note: If you REALLY want to speak (and understand Klingon), then you must get, read and STUDY The Klingon Dictionary, from Pocket Books, available at fine bookstores everywhere.
You might also say yIrojqu', peace! (yi-rohj-koo). On the other hand, this isn't likely a common phrase for Klingons to use. Don't be surprised if they take offense.