1/ I think you can change it yourself. They are arrow-left-enabled.png, arrow-left-disabled.png, arrow-right-enabled.png, arrow-right-disabled.png in the skin directory. You may wish to try replace them with bigger ones.
2/ There are 9 tap zones (3x3) this is usual layout for CR. I just did not support it completely and for now there are just few of them hard coded. But it will probably change in the future. serg_kv at the-ebook.org forum is making some changes for touch devices. You may wish to check his version
look here.