I'm not sure if this is possible but I've cc'd a couple of folks on the Tableau Mobile team that might be able to chime in.
If it's a case that the feature you want doesn't exist right now, please submit it as a feature request to our Ideas board. Don't forget you can vote on your own Idea
[Program Manager | Tableau Community Forums]
Thanks for this feedback. Question for you - are you asking for the ability to set the start page from within the mobile app, or are you wanting the ability for the mobile app to start on a certain view i.e. Set the Default Start Page for All Users - Tableau?