Is it possible to map to only certain fields in a Database table.
For example:

I have a table with 10 fields but really only ever need 2. So I create a class with 2 attributes and map to those 2 specific fields in the DB in my xml file. Is there a way this can be done, or do I have to map to every field in the DB.

yes - of course you can do this! Have you even tried to do it ? ;)
(the only "limitation" i can see is only how your primary key, constraints and indexes are at the db - you of course need to do something with columns that are required at the db layer....Hibernate don't care, but your db does ;)

Make sure that unmapped fields DO NOT have not null constrains on them and you should be fine.