Thanks for the tip!

Unfortunately, these queries returned empty result sets for me, though the server, schema and tables/views most certainly exist (and I can query them using OPENQUERY)

Actually what I was looking for was an equivalent to sp_help that I can run on Oracle. So something like:

select * from openquery(oracle, 'exec sp_help ''schema.table''')

replacing 'exec sp_help ''schema.table''' with whatever the equivalent is on Oracle.