I once saw some pictures of Kurdish men wearing the khanjar in the waist sash with the hilt towards the left. I believe this facilitates drawing with the right hand. I tried it, and it's easy to reach with the right hand, draw the khanjar out towards the left or in an upward movement and stab downward or slash towards the right.
The long jambiya's from the Asir could perhaps function as a parying weapon as well, protecting the right arm when drawn and used for slashing.
Drawing with the left hand would only be good for a forward thurst or an underhand stab I think.
Suggestions and speculations
Regards,
Emanuel