In a blender, combine 900 grams of cored and quartered tomatoes, 1 1/2 cups of canned tomato juice, 1 tablespoon of grated and peeled ginger, 1 teaspoon of ground coriander, 1 teaspoon of sugar, 2 tablespoons of extra virgin olive oil, and 3 tablespoons of lime juice.
Puree on full speed until liquified.
Pour the mixture into a large bowl and season generously with coarse salt and ground black pepper.
Refrigerate the soup for 1 hour until cold.
Taste the soup before serving and adjust seasoning if needed.
If desired, add cold water to thin the soup.
In a separate bowl, whisk together 1/2 cup of low-fat plain yogurt and the remaining 1 tablespoon of lime juice until smooth.
Season the yogurt mixture with salt and pepper.
Ladle the soup into individual serving bowls.
Add a dollop of yogurt mixture to each bowl, if desired.
Serve with toasted flatbread, if preferred.