Pour tomatoes with their juice into a saucepan, and mix in onion, sugar, salt, cloves, and black pepper; bring to a boil over medium heat, reduce heat to a simmer, and cook until the onion is tender, about 10 minutes.
Pour the soup into a blender, filling the pitcher no more than halfway full. Hold down the lid of the blender with a folded kitchen towel, and carefully start the blender, using a few quick pulses to get the soup moving before leaving it on to puree. Puree in batches until smooth and pour into a clean pot. Alternately, you can use a stick blender and puree the soup right in the cooking pot.
Return blended soup to the saucepan, and stir in the evaporated milk. Place over low heat, and cook just until hot, about 1 minute.