1. Place the bread in a large bowl, drizzle with some olive oil and squeeze out juice from one tomato over it. Add 1 teaspoon of sherry vinegar and mix it well with your fingers. Set aside, for at least 10 minutes.
2. Chop the onions and soak in water to remove some of the sharpness. Soak for 10 minutes then drain.
2. Transfer the bread mixture to a food processor and add minced garlic, cumin, cayenne pepper (if using) and salt. Process until very smooth.
3. Add half of the tomatoes, bell peppers, cucumbers, onions, generous pinch of salt and 1/4 cup of olive oil; process until smooth. Transfer to a large bowl and set aside. Repeat with another batch of vegetables and olive oil.
4. Add some of the remaining sherry vinegar, salt and spring water. Taste and adjust amounts of each to your liking.
5. Chill for at least 3 hours.
Divide between chilled soup bowls and prepare small dishes of chopped peppers, tomatoes, avocados and boiled eggs for garnish. Add side dish of olive oil for drizzling and serve with grilled bread.