I think its important to note that MCP was NOT made by Mojang, and that amazing amounts of work have to be put into this tool every version to keep it up to date and readable! Every variable in Minecraft source code has obfuscated names and every variable in Decompiled code that has a logical name was named by someone who took the time to understand the variable and what it does enough to name it.
((EntityPlayerMP)player).playerNetServerHandler.kickPlayerFromServer("kick message here");
Just remember to do your imports. player is Entity getting kicked, if you want to kick on command (ex. in my case command sender ) do sender instaed of player.
This answer is provided by We @ #Minecraftforge