I've been searching around to see if I can get an answer to this question. I've seen another player remove an immediately dropped chamber. Is there a command to remove chambers that you have created on the alien side?

There have been lots of times I would have loved to remove badly placed chambers by another player that are blocking movement, or are in real bad spots. I'm guessing that isn't an option in the game.

There have been a few times in haste I've dropped the wrong chamber, and wanted to destroy it or get the resources back. There have been times I've placed a chamber in a bad spot, and didn't realize it at the time and would love to get rid of it.

There is no way to do this in standard NS. I believe there is at least one plugin that allows this, though since its entirely 3rd party I don't really have any details.

There is a plugin which allows you to do this you have to point at the struckture you want to recycle and say "/rec" in the chat. Not all servers have this plugin though and you only get half of your res back.