Automatic factory reset and app installation
Possible solutions, in descending order of idealism and difficulty:


Create a custom ROM, with the apps you want on it, which you can flash onto these devices. This question is a good starting place for that.
Write your own app, which automatically installs the other apps. The first answer to this thread provides the code to install apps programmatically.
The easiest solution, if it suits your needs, would to be to use one of many "installer" apps. If you can drop the apps on the tablets after installing your stock ROM (ideally on an SD card), you could then install an "installer" app. Then either run it yourself, or instruct your users to run it and install the listed apps.


In any of these solutions, you will have to write the desktop computer application which has the few-button interface for users, which does the flashing and installing. Whether you do a custom ROM or a stock one, you will have to automate its install. This thread has some help on automating ROM installation.