Soak skewers in water for 45 minutes. In a mixing bowl, combine vodka, citrus, ginger, garlic, sugar, and miso paste and whisk until mixed. Slowly whisk in oil until smooth. Pour marinade over unpeeled shrimp and scallops. Cover and let marinate in refrigerator for 45 to 60 minutes. Skewer shrimp and scallops (4 to a skewer is optimal) and place on grill over direct heat. Allow tails and legs of shrimp to slightly blacken before turning. Scallops should brown slightly before turning.