Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   2      medium        onion -- chopped
   1      teaspoon      salt
     1/4  teaspoon      freshly ground black pepper
     1/4  teaspoon      cayenne -- up to 1/2, up to
   4      tablespoons   red wine vinegar

Preparation:

Combine all ingredients in small serving bowl. Mis well. cover and refrigerate for 30 minutes.