Arrange the shrimp and scallops on a plate in a steamer basket. Sprinkle with 1 teaspoon each orange juice and rice vinegar. Place steamer over boiling water in a wok or large skillet and cover. Cook 7 to 8 minutes until shrimp are cooked through. Meanwhile, stir together remaining orange juice, rice vinegar, sesame oil, mustard, salt and pepper in a medium bowl. Mix in scallion, dill and chives. Transfer hot seafood to bowl with vinaigrette; toss to coat well. Serve warm on lettuce lined plates. Garnish with chopped pimento if desired. Makes 4 servings. PER SERVING: calories 116, protein 14 g., fat 4 g., carbohydrate 4 g., cholesterol 66 mg., sodium 395 mg. FROM: Light & Easy Meals from Family Circle Magazine issue August 1992.