Icon hiding and home/back keys



So,I have today developed my first,fully working project,but I would like to solve 2 things...
1. Is there a way to hide app icon from the list of running programs(so it will work as resident)?
2. Can I use the backarrow key on Smartphones in my software without hiding the form? I need in some cases to use it for loading previous page and when I am at the first page,it will minimize the form and switch me into previous running application. How can I handle it?

Thanks in advance,Tomas.