1. Segment the orange and grapefruit by cutting the top and bottom off, and placing cut side down on the cutting board. Run a sharp pearing knife or utility knife between the peel and the flesh of the fruit. Continue until all of the peel is removed. Hold the each fruit over a bowl, and cut between the membranes to remove the half moon shape segments. Continue until all are removed and squeeze the remaining membrane of all its juice. Strain the segmented fruit from the juice reserving the juice and set the juice and segments aside.
2. Whisk the yogurt, olive oil, vinegar, sugar, soy sauce, mustard, hot sauce, parsley, and citrus juices until well blended in.
3. Toss the citrus segments in a large bowl with the cabbages, scallions and pepper. Add the yogurt dressing, and mix to combine. Let sit 10 minutes before serving.
Per serving: 69 calories, 2g fat, 1g saturated fat, 3mg cholesterol, 136mg sodium, 9g carbohydrate, 3g fiber, 5g sugars, 3g protein