A stranger in a dream rarely represents an actual unknown person -- more often it's a part of yourself you haven't recognized yet, or a quality you're growing into. Pay attention to how the stranger makes you feel: that reaction is usually the real message, more than anything they say or do.
The Moon should be asked for fluidity of movements, disclosure of secrets, abundance of waters, extinguishing of fires, invalidation of completed facts and dissolution of harmonic atmospheres. - Picatrix (Andalusia, ~1000.AD)