In a food processor puree the scallions, bell peppers, cucumbers, garlic, tomato juice and olive oil. Add 1 to 2 tablespoons of vinegar and season to taste with salt and pepper. If you find the mixture too thin, add the cubed dried bread and puree gain until thick enough for your taste. Cover and refrigerate at least for 1 hour until serving time. Garnish with sour cream, cucumber and scallion.