I am trying to get a listing of all the columns within every table that belong to a certain user.

I can get a listing of the tables using this query.

select OWNER,OBJECT_NAME from all_objects where object_type = 'TABLE' and owner = 'user';

is there anyway to get a 'desc' done on all of the tables that I am retrieving?

You can generate your own script something like...

select 'DESC ' || OWNER || '.' ||OBJECT_NAME from all_objects where object_type = 'TABLE' and owner = 'user';

the result is a script what you can run

you should connect to db by sys user.
for example: connect sys/password as sysdba
you run the script,you can get what you want :

SELECT a.owner,a.object_name,a.created,a.last_ddl_time,a. timestamp,a.status
FROM DBA_OBJECTS a
where a.owner in (select distinct owner
                  from dba_objects
                  where owner not in ('SYS','SYSTEM'))
order by a.owner desc;