You do not HAVE to fix a "fix it" ticket if you are willing to pay the charge for the citation itself, which is about $200. If you did not fix the tint and have it signed off before you left California, it would probably be cheaper just to pay the full fine. You can do that online (this is not a DMV point so you need not worry about that). Go here and follow the traffic link for the county where the citation was issued:
http://www.courts.ca.gov/find-my-court.htm