1. 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.
  2. Cut cucumbers into chunks (if using thick-skinned cucumbers, peel and seed them first)and combine cucumbers, watermelon rind, vinegar and salt in the processor. Purée until smooth.
  3. Add to the other purée and whisk/blend together well.
  4. Add more salt and vinegar if desired. Chill for at least two hours before serving.