If it didnt' come with an LCD, it probably isnt' compatible with one. There is no "standard" of connections or communication yet.
Even if it is, it will only be compatible with that brand's LCD, and will only display or respond to whatever it's been programmed to do from the factory. If the seller offers an LCD with it, get that one. Otherwise, chances aren't great to get any "random" LCD to work with it.
You can look up threads with LCD in the title here on ES, and find similar issues with other controllers.
Also, not all controllers, or LCDs, can display or set everything that another combination could.
You *can* use the SA version of the Cycle Analyst from Grin Tech http://ebikes.ca to display a bunch of useful info, but it doesn't communicate with the controller at all--so if you want something to talk to the controller, you should get it as a kit with the controller, to be sure it will work.