PostgreSQL to MS Access
In your situation, I would just spin up a PostgreSQL database somewhere and have them connect to it in Microsoft Access via ODBC.

http://www.postgresonline.com/journal/archives/24-Using-MS-Access-with-PostgreSQL.html

And I would keep Access and its limitations and tradeoffs in mind while designing my PostgreSQL database. 

Advanced features will require you writing pass-through queries to leverage PostgreSQL features directly, but they don't play at all with Access tables, and if you're going to be doing any updates, you're going to need custom code because pass-through queries are read-only.

I would definitely familiarize myself with Access as well: 

https://msdn.microsoft.com/en-us/library/Bb221186%28v=office.12%29.aspx 

and go through some tutorials:

http://www.gcflearnfree.org/access2013

Actually translating the PostgreSQL database to Microsoft Access would likely be a long, tedious process fraught with pain and peril as has been said, and is not recommended.