1/4 cup chopped onion
1/4 cup peanut oil
2 tablespoons rice wine vinegar
2 tablespoons 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
dash salt and pepper
Combine all ingredients in a blender or food processor and process until smooth.