Uh, noise, in space or dirtside does not affect light which is what a laser is.
The sand would have to be powdered form and it would take more than one cannister to be truly effective, but the sands purpose is to disrupt the "cohesive" nature of the light of the laser, dispersing it (like the light from headlights in a fog.)
Without an atmosphere (wind and such) the sand will only have the deviations to direction caused by one particle bumping in to another to cause it to disperse, lasting long enough for several rounds of battle.
Just my own uneducated reasoning. If it sounds too stupid, please educate me.