Drop this in your shell's config:
For ZSH:

function command_not_found_handler(){
    junest -f -- $@ || echo "Command not found:" + $1
}

For BASH:

function command_not_found_handle(){
    junest -f -- $@ || echo "Command not found:" + $1
}

And now any commands that are not found on your native linux system, get tried inside of junest!