Yes, you can report this incidence to police. Especially, if he slaps you in public. Just bring a witness with you. A qatari would be perfect.

If the slap is still fresh... it still is a proof enough. just report this incidence so that the police will have a record of this man's violent actions. Later on, if he does this to another woman... police will know his inclination to physical offenses.

Hope you won't let this guy get away.

i know of the same case. the guy got a record and a small penalty. however, its worth it.