In a medium mixing bowl, whisk together the Less Sodium Kikkoman Soy Sauce, Kikkoman rice wine vinegar, sesame oil, sesame seeds and red pepper flakes until combined.
Add the cubed tuna and scallions and mix with a spoon. Mix gently as the fish is delicate. Mix until tuna cubes are covered in the dressing. Cover with plastic wrap and let marinade in refrigerator for at least 20 minutes. This will allow all the flavors to enhance, do not skip this step.
Once marinated, scoop poke into bowls and top with more sesame seeds and scallions. Serve over brown or white rice, chopped romaine lettuce, seaweed salad, or simply eat it as is!