I didn't know that it was possible. I was looking for a solution to kick a player with their steam ID and the solution is just to use the kick command with the steam ID instead of the nickname ...
RustAdmin RCON Tool
Efficient RCON tool to manage your server and its players (written in C++)
Total Downloads: 23,581 - First Release: Sep 24, 2014 - Last Update: May 15, 2018