Sprinkle cubed bread with 3 tablespoons water; gently squeeze out excess moisture.
In blender in batches, blend bread, tomatoes, onion, green pepper, garlic, cucumber, oil, sherry vinegar, white wine vinegar, salt, sugar and 3/4 cup cold warer until smooth.
Strain through fine sieve into large bowl, pressing and discsarding solids.
Cover and chill for 1 hour or up to 24 hours.
GRILLED SHRIMP: Meanwhile, thread shrimp onto soaked wooden or metal skewers.
Brush with oil; sprinkle with salt.
Place on greased grill over medium-high heat; close lid and grill, turning once, until pink, about 5 minutes.
Divide soup among 4 bowls; drizzle with more olive oil, if desired.