Seafood Pasta Salad

1/3 c. olive or salad oil 1/3 c. lemon juice 1/3 c. wine vinegar 1/2 tsp. salt Dash of white pepper 1/2 tsp. dry mustard 1/2 tsp. paprika 1/4 tsp. sugar 1/4 tsp. garlic powder   Combine ingredients in jar with tight lid. Shake well. Let stand 30 minutes or more for flavors to blend. Shake well just before using.   SALAD:   2 1/2 c. mixed, cooked or canned seafood 4 c. cooked pasta shells 3 green onions with tops, sliced 3 parsley sprigs, chopped 1/3 c. coarsely snipped fresh dill or 1 teaspoon dried dill weed 1/2 c. finely chopped celery Salad greens   Pour half the dressing over seafood and let marinate at least 30 minutes. Rinse pasta well with cold water; drain thoroughly. Add onions, parsley, dill, celery, and remaining dressing; mix well. Add seafood with dressing; toss lightly. Cover and refrigerate. When ready to serve, stir pasta salad and place in serving bowl. Add salad greens. If desired, garnish with fresh dill sprigs and black olives or cherry tomato halves. 6 to 8 servings.