I believe if you toggle Self Service from app to web clip it uninstalls
the native app. After an interlude to allow for the installation of the
web clip and uninstallation of the app, switching it back prompts the
installation of the Self Service app...
Alternatively, after the creation of the site, if you go to an existing
computer and click the edit button in the information pane while the
general tab is selected, you'll be able to select a site from the site
drop down.