A wireless communication network serves a User Equipment (UE) over an optimal wireless network slice for a user application. The wireless communication network receives a download message when the UE downloads the user application that indicates a UE Identifier (ID) for the UE and an application ID for the user application. The wireless communication network selects a slice ID for the optimal network slice based on the application ID for the user application. The wireless communication network transfers a slice message to the UE that indicates the application ID and the slice ID. The wireless communication network exchanges application data for the user application with the UE. The wireless communication network processes the application data with the optimal wireless network slice.