You have a few options:
If the controller can source enough power, you can run the two lights in parallel. You would need a Y cable.
If the controller cannot source enough power, and you can route a cable straight from the battery, you can use a relay as an on/off switch for your direct connection. The original light cable from the controller would be used to control the relay. This lets you use the controller to turn the lights on and off.
In either case, if the voltage driving the lights is high enough, you can consider running the lights in series. The series connection will cut the voltage across each light in half, but keep the same current. The parallel connection will provide the full voltage across each light, but the current to each light will be cut in half. The wattage of the light is the voltage multiplied by the current, so there should be is no difference in the light output, it is more a matter of wiring convenience.
Some lights may be more efficient at a certain voltage or current, meaning that more of the wattage is producing light and less is wasted producing heat.
