1/4 cup chopped onion
1/4 cup vegetable oil
2 tablespoons rice wine vinegar
1 tablespoon water
1 tablespoon chopped ginger root
1 tablespoon chopped celery
1 tablespoon soy sauce
1 1/2 teaspoons tomato paste
1 1/2 teaspoons sugar
1 teaspoon lemon juice
1/2 teaspoon salt
Combine all ingredients in a blender. Process until almost smooth.
Any unused portions may be stored in a covered container in the refrigerator.