I have an Access database on a PC and want to write a small App, that can CRUD the data in this database. I would write a simple C# service that provides this functionality, but
Check out MSN-REST-WCF. This is at a basic level. But should give you something to start with.
Using the concepts of REST has ZERO to do with an Oracle database.
Using the concepts of REST has ZERO to do with a MySQL database.
Using the concepts of REST has ZERO to do with an SQL server database.
Using the concepts of REST has ZERO to do with an Access database.
So building a web site using REST is 100% neutral and has ZERO to do with the particular database system.
How you build a web site using REST with MySQL server or an Access database does NOT change.
So virtually any article on the web that shows one how to build a web site based on REST will apply to ANY database, and asking such a context in regards to Oracle, or Access makes ZERO sense.
How a REST site works with Oracle, or how a REST site will work with Access will not change.
Now of course we only talking about the data. The forms UI etc. used in Access application cannot be used for web based systems and there no real context of talking about VB6 forms, c# (desktop winforms), or Access desktop forms have ZERO relationship and ZERO context in regards to building web sites based on REST.