Question: I'm using a tablet with Android 2.2. Is there something like `Tab` to switch to the next form field?

Answer: 
Is this what you are looking for [paid app]: <https://play.google.com/store/apps/details?id=com.vmlite.vncserver&hl=en> 

However, if you are willing to go through a lengthy process [but free], you can follow the tutorial [here](http://www.howtogeek.com/howto/42491/how-to-remote-view-and-control-your-android-phone/) to access your phone via PC.
Use a USB-OTG cable to connect a mouse. You can even make your own by cutting and soldering a microUSB cable to the female end of a USB extension cable.