To prepare onions, combine water, red wine vinegar and sugar in a small saucepan. Bring to a boil and then remove from heat. Reserve 2 Tbsp. vinegar mixture. Combine remaining vinegar mixture and onion in a small bowl. Cool to room temperature.
To prepare dressing, combine 2 Tbsp. vinegar mixture, orange juice, oil and mustard. Stir well with a wire whisk.
Combine dressing and salad greens in a large bowl and toss well. Divide salad greens evenly among 6 plates. Top each with 1/3 cup of oranges, about 2 Tbsp. onions, 2 Tbsp. walnuts and 1 Tbsp. of pomegranate seeds.
Yield: 6 serving