It shouldn't hurt the glass surface of the module but you will need to keep them clean to maximize power output. the racking/mounting system will more than likely be susceptible to corrosion from salt accumulation. The right materials, finishes, and fasteners must be selected and then a regular washdown should be performed. Much like maintaining a boat.

I have solar panels and many neighbors also have them on a salty beach and they are holding up great. I wish I could say the same thing about wind generators.