Combine diced tomatoes, cucumber, bell pepper, onion, jalapeno, garlic, and corn in a large bowl.
Place Roma tomatoes, lime juice, olive oil (if using), water, balsamic vinegar, and sugar in a blender. Cover and puree until smooth. Pour pureed mixture through a strainer into the vegetable mixture; stir to combine.
Place 1/3 of the soup mixture into the blender. Blend until smooth. Add to the remaining soup and stir to combine. Cover and refrigerate for at least 2 hours until thoroughly chilled.
Add salt, black pepper, and thyme to taste. Ladle into bowls and top with fresh basil.
Yield: 6 servings