Pull the leaves from the bottom stems and wash them in cold water.  Tear the leaves up  a bit. Heat up a sauté pan and put the greens in, still containing the wash water. Cook over a low heat. While they are cooking sprinkle a small amount of red wine vinegar over the leaves, plus some salt and pepper. After the greens have steamed down and softened, sprinkle some olive oil and a bit of sesame oil on them and distribute throughout the pan.  They are done when fully softened.  You can usually be sure that they are done when they change color.