Newbie - Start-up Grub Question

Completely new to linux. Successfully installed a USB bootable onto my Surface Pro 7. My plan is to use Kali off the USB drive until I am completely comfortable with Linux, and tackled all the hardware issues (like touch screen usability etc)

I installed the full -live version. I use the persistent non-encrypted mode.

Everything works fine

Question:

1) What (and How) do I need to do so that it by-passes the initial Kali page and goes straight to the persistence mode

2) I have a 30GB USB drive, what (and how) do I Maximized usable USB drive space

Newbie - Start-up Grub Question - USB install