Ingredients
1 cup loosely packed parsley or mint leaves, or a combination of the two
1 stalk celery, cut into chunks
1 dozen cherry tomatoes
1 clove garlic
1 ½ cups bread cubes, like ciabatta or sourdough
5 tablespoons olive oil
About 2 pounds cucumbers (about 4)
About 2 pounds cubed watermelon rind, pale pink and green parts, hard skin removed about 8 cups (from 1/2 watermelon)
1 tablespoon sherry vinegar or rice wine vinegar, more as needed
1 tablespoon salt, more as needed
Tip: total weight of cucumber and watermelon pieces should be 4 pounds, but it is not necessary to use precisely 2 pounds of each

Directions
In a food processor or high-speed blender combine almonds, herbs, celery, tomatoes, garlic, bread and oil. Purée until smooth and transfer mixture to a large bowl. Cut cucumbers into chunks (if using thick-skinned cucumbers, peel and seed them first). Working in batches, combine cucumbers, watermelon rind, vinegar and salt in the processor. Purée until smooth. Add to the other purée and whisk/blend together well. Add more salt and vinegar if desired. Chill for at least two hours before serving.