In a small bowl, combine the pomegranate juice and orange zest, vinegar, shallots, salt, pepper and mustard and whisks thoroughly to combine. Add the oil in a steady stream and whisk until emulsified. Fold the segmented oranges and sliced onions into 1/4 cup of the dressing and toss to combine and set aside.
Wrap each slice of goat cheese in a slice of prosciutto. Heat a large skillet over medium high heat. Add the wrapped cheeses and sear on both sides. Remove from the heat.
In a large salad bowl, combine the greens. Add the marinated orange sections and onion slices, and toss gently with enough extra dressing to coat evenly. Divide among salad plates and top each with a seared goat cheese package and a sprinkling of pomegranate seeds. Spoon a little extra dressing over each salad and serve immediately.