You can probably do something along the lines of what you want using external tables with the datapump driver -
create external table x as select * from a union select * from b;
copy the resulting file to new server
recreate external table defintion in remote database
ctas table you want as select * from external table.
Not sure if this has any real benefit of doing individual exports of the 2 tables and then manually bringing them together but it may some some space effort and time?
The initial part of this is something similar to this blog http://blog.mclaughlinsoftware.com/oracle-sql-programming/creating-an-external-table-that-uses-oracle-data-pump/ and you should be able to figure out the rest?
See what you think?
The good news is that you can use data pump to export a view (or views) as a table, utilising the VIEWS_AS_TABLES parameter.
See Data Pump Export documentation.
The not so good news is that this is a new functionality in 12c and you will have to upgrade before you can take advantage of it.