Heat the oil in a large frying pan on medium-high heat. Add the collard greens, and cook until they turn bright green and begin to wilt, 4-5 minutes.
Add the rice vinegar, stirring well to coat the greens, and cook just about two minutes more.
Video
Notes
You want to chiffonade your collard greens, meaning slice them into thin ribbons. See the video for a visual of how to do this.Leftovers will keep for 3-4 days in the fridge.