Remove crust from bread and soak in a little water. Peel the onion and garlic and finely dice both. Make crosswise slices in the tomatoes and pour into a bowl of boiling water. Then place in cold water and remove skin. Cut the tomatoes into quarters and remove the seeds. Peel the cucumber, halve lengthwise and remove seeds. Rinse the bell peppers, peel, halve and trim.
Set aside about a quarter of the chopped cucumber, bell peppers and tomatoes. Cut the rest into chunks and puree. Squeeze the toast well and mix with the onion and garlic in the vegetable puree. Then add cold water to the puree (about 250 ml) (approximately 1 cup) and dilute to the desired consistency. Add the vinegar and olive oil and season the gazpacho to taste with salt and cayenne pepper.
Cover the soup at least 30 minutes and allow to cool. Before serving, distribute into glasses and sprinkle with the small diced vegetables. Serve and garnish with cilantro leaves.