How to Expand Data Store Omnirom 5.1.

Hi Everybody ;

İ'm new at forum also custom roms My device is Samsung Galaxy TAB 7 P1000 İ've installed Omnirom,But after installed i've realized that data store on Apps space is 1.5 GB and quickly it became full .the device has 16 GB disk and in this situation free size is about 12 GB on total space

İ can not install and app because of disk size İs there and solution to fix this problem

Expand screen to edge

Is there anyway to fullscreen the edge so it hides the panel on the side for example when i watch youtube it fills the whole screen or when I chromecast it hides that Galaxy Note edge on the top with the black bar?