Using saltwater to fight the wildfires could have a major negative effect. The saltwater contamination could prevent grasses from growing in the sprayed soil. No grass or weeds and you get mud slides. A viscous cycle, wildfire or mudslides, just like always in California.
With their kinds of fires nothing grows back because of topsoil erosion. Answer? Find salt thriving vegetation to help reclaim. My bet is after a couple of rains the salinity levels would drop substantially anyway.