Folks,

Can Hibernate's caching be turned off completely and easily?

The database used by our application is also accessed from another legacy system, which is continuously modifying the data, so we cannot afford to perform any read caching within our JVM.

I've read a few posts here and there about the use of CustomSessionFactories and the flushing of sessions, but is there a quick, obvious way of turning off all caching?

You can't turn off the first-level, Session cache. Use short Sessions, for a single database transaction, and you won't have any problems.