Combine wheat berries, water, salt, and 2 teaspoons basil in a medium stockpot.
Bring to a boil over high heat.
Reduce heat to a simmer and cover; stir every 10 minutes.
After an hour, remove from heat and drain.
While wheat berries cook, cut tomatoes into segments, and remove pulp and seeds.
Place seeds and pulp in a blender and puree, then strain through a fine mesh sieve into a small bowl.
Dice tomato segments.
Remove corn from cobs.
Transfer drained wheat berries to a large bowl. (Add spinach now, if using.)
Add tomato juice, diced tomato, corn, and remaining basil, stirring well.
Season with salt and pepper to taste.
Refrigerate for at least 2 hours.