Put tomatoes, garlic, cucumbers, red bell peppers, and onions into a large bowl and toss to combine. Working in batches, puree vegetables in a blender or food processor until smooth, adding a little water if mixture seems too thick. Strain puree through a medium sieve, discarding peels and seeds.
Place half of the strained puree back into the food processor, add vinegar, and puree again. With food processor still running, drizzle in the oil. (This will turn the soup slightly orange.) Return to bowl with remaining puree, stir well and season with salt. Cover and chill thoroughly, then ladle into bowls and serve topped with some chopped cucumbers for the crunchiness.