Do you mean the dimmed/standby watchface, or the brighter one that shows up when you touch/tilt the watch? The G Watch has a few watch faces that show the date all the time, and show a seconds-hand when brightened. These include "Dieter", "Helvetica", and "Aviator". None of the faces show the second hand when dimmed, I suspect to save battery life.
I created the watchface designer WearFaces, but it inlcudes also premade watchface packs. Currently it supports also seconds hands. The date option will be added soon.