Connect to Oracle from SQL Server
Oracle uses a case-sensitive catalog, and hides that ugly fact from you by silently converting non-quoted identifiers to all caps, both in DDL and DML.  

The name of your table is actually RS.RS_MYAPP, and SQL Server may be sending the identifier to Oracle as "rs"."rs_myapp", which would fail at Oracle.

So try

select * from [rstest-Link]..RS.RS_MYAPP