Trim and chop collard greens. Heat the oil, add the mustard seeds, stir and add the chili, and the dried ginger. After a few seconds, add the onion and saute. Add the collard greens and a pinch of salt, cook until wilted. Add a 1/2 cup of water, cover and cook for about 15 minutes on medium-low. Stir in garam masala, then serve.