A counter strike map with only grenades

What you're looking for is called remote-console, or rcon. It's built right into the game; to use it, set rcon_password to the same value on the server (in server.cfg) and client (in the console), then type into the client-console rcon <command> for any commands you want to run on the server.

You can use rcon outside of the game, too. The most popular tool for this is HLSW.

In the server menu is an option to search for VAC-secured servers There are NO official steam servers, There are only induvidual gamers and communities who run these.

Just looking for VAC secured servers should be enough to prevent having to deal with hackers. Othwerwise consider joining a community that has some good servers (I will not name any) Most bigger communities have admins on at most times and when you stick around them you might find some guys/gals who are great to hang around with.

Also consider that some people aren't actually hacking alltough I would allways accuse them of doing so, CS is one of these games where some people just developed insane skills