open the build menu, then look in the center of the top of your screen, under the forge points. there's a $ - that's to sell buildings ( = destroy them). the "overweight arrows" next to the $ let you move things.
and you'll get more land by doing research, conquering certain sectors of the continent, and/or by winning medals in the pvp tournaments.
i really recommend the "guides" section of this fine forum - there's miles of great information there. have fun!