If you are on windows then you want to go into the options and (IIRC) change the “Windows size X/Y” options. That should resize the game (though you might need to resize the window separately.
If you are on linux, OSX, or Cygwin on windows, then you just need to change the terminal size before launching the game. If you are loading from an app you might need to check the preference menu of your terminal program to set the default terminal size in order to change that.