Cusp, you didn't specifically mention the client that you are using to log into Salem. If you are using the default client then you have no options to zoom or expand the mini map. If you use the Ender Client you can expand the mini map window as well as zoom in and out of the map (showing a limited number of map tiles that you have visited during that session since logging in or porting or entering a mine or building).
You can visit the Artifice & Arcana forum to get more information on thrid party clients, etc. Here is a link to the thread for Ender Client.
http://forum.salemthegame.com/viewtopic.php?f=11&t=50Current download information can be found updated at the top of that thread.
Once you are using the Ender Client, mini map tiles will be stored for you on your computer. There is a setting in options to toggle it on and off. You can then use the Salem Map Tool to construct your own maps of areas you explore.
http://code.google.com/p/salem-map-tool/You can also contribute your map tiles to the active Map Project linked above if you wish.
Happy Salem