We had a requirement to create .app packages of our Xamarin Forms application for submission to a third party. The requirement was to create this for a iPhone 6 iOS 10.2 Simulator.
Initially I thought rebuilding the solution in Visual Studio 2015 would be enough as this would create what looked like the .app package however when using the following command line :-
xcrun simctl install booted /users/[username]/desktop/certificates/[username]/[packagename].app
This resulted in a "Failed to chmod : No such file or directory" error.
To resolve this issue I found that along with rebuilding the solution in Visual Studio, you need to deploy the application to the simulator, which inflates the .app package file by ~50MB, and on inspection of the before and after .app packages, the DLLs and EXE are included which allows the .app package file to be deployed to the simulator successfully, using the command line above.