This is how to do it on 8, click here.
As for cloning to a flash drive I've not heard if it is possible. What you could do is to create an image on the usb drive and use a recovery DVD to load back the image. You will still need an optical drive.
It's possible to create a bootable usb drive so that you can install 8 from it, click here.
EasUS is well thought of and two free programs you should look at,
Todo backup. Hope that helps a bit.
I use Paragon Harddrive Manager Pro, otherwise I'd have given EasUs a go.