Coming in a bit late but you can definitely do a fish only tank without live rock, protein skimmers or corals. You can use dead rock and dead coral (though I don't recommend buying large pieces of dead coral as they often contribute to reef destruction) for decor, or fake stuff.
Doing a fish only system is very similar to doing a freshwater system. Check out the books and let us know if you have any questions.

One of the absolute best is
Marine Fishes by Scott W. Michael. Invaluable!