In a large bowl, whisk together Kikkoman® soy sauce and lime juice.
Whisk in garlic, ginger, and sesame oil.
Reserve a little of the marinade for basting or serving on the side.
Add fish fillets to the bowl. Cover and marinade for at least two hours.
Preheat heat over a low to medium flame.
Prepare a sheet of foil with non-stick cooking spray and place it on the grill.
Add fish fillets to foil sheet. Close grill lid and cook for 3-4 minutes.
Use a spatula to flip fillets. Cook for another 3 minutes, or until fish is cooked through and flaky.
Serve fish over a bed of fresh veggie slaw on soft taco shells.
Garnish with fresh cilantro, if desired.