No idea on the Cali laws, but I do know how to remove tint.
1.Completely coat one window with an amnonia based window cleaner, soak it good.
2.Place a black piece of plastic over the window. Half a garbage bag works pretty well.
3.Let car sit in the sun for 30-45 minutes. It needs to be relatively warm for this to work. This reactivates the glue to some degree and allows it to soften.
5.Work an edge of the tint loose with a razor blade and start peeling it off. It will rip so you'll have to do this many times.
6.Once all the tint is removed take the razor blade and scrape the window removing any remaining glue. If glue remains and it has started to harden, repeat the amnonia/plastic bag thing.
Take it to a tint shop to have them remove it.
A word of warning, typically second tint jobs are not as clean as the first time. It is nearly impossible to remove all the glue and it will become visible on the next tint job.
Hope that helps.