Cut eggs in half lengthwise. Remove yolks and set whites aside. In small bowl, mash yolks with fork. Stir in yogurt, onion, parsley, juice, mustard, salt, if desired, Worcestershire, pepper and paprika until well blended. With spoon or pastry bag, refill whites using about 1 tablespoon yolk mixture for each egg half.
OR, place yolks in food-storage bag. Add remaining ingredients, except egg white halves, to the bag. Close bag. Knead the bag until everything is well blended & smooth. Push the contents toward the corner. Snip about ½-inch off the corner of the bag. Squeezing the bag gently, fill the reserved whites with the yolk mixture. Chill to blend flavors.