Are my personal data secure with Simple Search Bar?

We only collect anonymous statistics data in order to measure and improve the service. Search terms are sent to Yahoo! using an encrypted protocol (https). Search results are provided exclusively by Yahoo! also via https

Can I hide the search bar when I don't need it?

Of course. Just click the "hide" button next to the search button. You can re-activate the bar later on, clicking the "unhide" button that will become available immediately.

Can I uninstall the program?

If you decide to uninstall, go to Chrome menu, open More Tools -> Extensions, locate the Simple Search Bar extension and click the "Remove" button.