No such functionality is delivered out-of-the-box with Mendix. This does not, however, mean that you can't fulfill your client's requirements.
If you want an example/proof-of-concept I'll write one for you, so let me know here.
In index3.html, inside the HEAD tag, you should see these lines,
Right below these lines, add the following code (which I've adapted from other implementations found on the web and tested in IE, Firefox and Chrome),
This will prevent the right-click event from propagating (if the conditions are met, the handlers return false) and effectively disable right-click.
Hope this helps.