1/2 cup mayonnaise
1 1/2 teaspoons distilled white vinegar
1/2 teaspoon Worcestershire sauce
1/4 teaspoon salt
1/4 teaspoon paprika
1 teaspoon dried parsley
2 tablespoons grape juice
In a small bowl mix together mayonnaise, vinegar, Worcestershire sauce, salt and paprika.
Place tomatoes in a large bowl; add onion, and grape juice. Cover bowl and refrigerate.