(nmap map:"<ctrl-a>" to:"!!open 'peepopen:///path/to/your/code/folder?editor=vico'; return true; <CR>")
ctrl-a will then open peepopen and the selected file will be opened in vico.
(edit: never mind, I went ahead and got it)
(nmap map:"<ctrl-a>" to:"!!open 'peepopen:///path/to/your/code/folder?editor=vico'; return true; <CR>")
ctrl-a will then open peepopen and the selected file will be opened in vico.