iSSH includes an "Esc" key on-screen, but hitting the screen like that is lame, and, in the case of a sufficiently flimsy iPad stand, will cause your iPad to fall over. There's a much better way.
First, go into your connection configuration in iSSH, hit "Advanced," and set your term string to "xterm-ipad."
/etc/terminfo/x/xterm-ipad. This lets the server know that it can communicate with iSSH like a normal ssh session.
Then add this to your .vimrc:
3 if &term == "xterm-ipad"
4 nnoremap <Tab> <Esc>
5 vnoremap <Tab> <Esc>gV
6 onoremap <Tab> <Esc>
7 inoremap <Tab> <Esc>`^
8 inoremap <Leader><Tab> <Tab>
Big thanks to Alf Mikula and Doug McInnes for showing me how to fix this. The only thing to watch out for with this solution is that it doesn't break tab-completion. So if you do:
And press Tab, you'll get
:r filename. And if you keep hitting Tab, you keep getting tab-completion. So it's kind of a Tab dead zone, but beyond that caveat, it works beautifully.