Add the tomatoes, cucumber, garlic, bell pepper and shallot to a large bowl and toss together with a big pinch of salt and pepper. Add to a blender and blend until smooth (you may have to do this in batches). Then drizzle in the olive oil and vinegar with the blender running. Place back in the bowl, cover and refrigerate for at least 1 hour for the flavors to develop and for the soup to chill.
Ladle soup into bowls and drizzle with olive oil to serve.