Use any graphic tool to create/edit cursors
I use MicroAngelo, but there are dozens
Then you create a resource DLL in VC++, you add your cursor with a resource ID, generate the .res,
add the .res to UWP project in .csproj :
<Win32Resource>DLL_Resources.res</Win32Resource>
then you can use it with the resource ID :
Window.Current.CoreWindow.PointerCursor =
new Windows.UI.Core.CoreCursor(Windows.UI.Core.CoreCursorType.Custom, 101);
Test with a red cross :