I want to have transparent square tile for my app, but in the Store it should have green background behind same icon. Is there any way to achieve that? In 8.1 we had (still have) 300x300 "App tile icon" which is used for the Store I believe, but now it seems store using image from Package.appxmanifest, and even if I explicitly set non-transparent image for "Store Logo", it doesn't work.
Question is: is that at all possible to have transparent tile for start screen but solid-color background icon in the Store?
Yes, "App tile icon" is used only on Windows Phone 8.1 or earlier and in practice for UWP apps medium tile is used to represent app in the Store. StoreLogo -- is actually a small icon and is used in relevant scenarios (like ones you already mentioned).
A possible workaround could be the following:
- use solid-color background icon as default tile so that it will be used in the Store, and
- update tile with another transparent image once application was launched (just don't set expiration date).
p.s. Some apps also use such approach to provide users choice whether they like to use branded color on tile or to use system accent color instead.
When I create an UWP app within Visual Studio, a unique file is made for the windows store logo: StoreLogo.png. Can't you just edit this file to be opaque? 
来源：https://stackoverflow.com/questions/37583687/transparent-tile-but-colored-icon-for-the-windows-store