Good luck with that.
Congress has exclusive authority over immigration. The Executive has only that which Congress has by law delegated to it, such as the “travel ban” which temporarily restricted entry from terrorist nations.
The President can stop all immigration any time he wants.
The Executive Branch implements those laws and has lots of prosecutorial discretion. It was the Executive Branch that sued the state of AZ for trying to enforce federal immigration law. The Executive Branch makes the decisions on who gets visas.