Hi Eva,
Choice of venue provisions in contracts may control where a suit must be filed, if they are properly worded, but not always even then. Some courts will not enforce an inequitable choice of venue clause.
Aside from that, the answer to your question depends on California's long-arm statutes. I am not admitted in California, so I do not know for certain, but most states allow for state courts to exercise jurisdiction over a party who committed a harmful act outside of the state that harmed a state resident.
Enforcing the judgment is another matter, but my sense is that the small claims court clerks would be helpful in providing assistance as to how to go about it.