In medium saucepan combine orange juice and ginger; bring to a simmer and add pork cubes. Simmer for about 5 minutes, until pork is cooked. Remove pork and remaining liquid to bowl, refrigerate uncovered to cool slightly, about 5-10 minutes.
In medium bowl gently toss together melon, papaya, Grand Marnier, pork cubes, and cooking liquid. On each of four plates place 1 1/2 cups salad greens. Serve equal portions pork-melon mixture atop greens, topped with 2 tablespoons yogurt.