Hazel contact lenses are a very good color for a teen with dark skin. Hazel is a light brown with a little green in it that looks beautiful against dark skin, while still looking natural. The lighter brown color of hazel eyes stands out when paired with dark skin.
If having a natural look is not a big concern, green color contacts are also a good choice to be paired with dark skin. People are mesmerized by light eyes paired with dark skin (for instance, the picture of the Afghan girl on the cover of National Geographic). Green eyes with dark skin will draw a lot of attention to the eyes, but won't look as natural as hazel or plain light brown.