Chilled soups that need little or no cooking are great for summer. This recipe from almost 20 years ago is excellent. It helps to have a food mill but, if you don't, the tomatoes can be skinned and pureed in a food processor or blender. Both the Joy of Cooking and Alice Waters give the same advice for removing the skins from tomatoes. Put them in boiling water for fifteen seconds to a minute picking one up now and then to test whether or not the skin is starting to come loose. Plunge them into ice water. "Slip" the skins off --- if someone tries this, please write a comment.
The rest of the soup is very easy.
The celery gives the soup a pleasing crunch. This goes well with crostini spread thinly with goat cheese.
In a small saute pan, cook the oil, garlic, paprika, cumin, and cayenne for about three minutes, stirring constantly. Remove from the heat and set aside.
Pass the tomatoes through the large holed disk of a food mill. You kind of have to wrangle this tool over a bowl. I sort of wedged it up against the edge of a sink. Stir in the cooked spice mixture, the cilantro, vinegar, lemon juice, about a tsp of salt, celery, and 2 Tbsp water. Adjust the seasoning and chill until cold. Garnish with sprigs of cilantro.