Massage the marinade into the fish, ensuring both sides are well marinated. Set the fish aside to further marinate for about 30 minutes to 1 hour.
While the fish is marinating, cut the snow peas into two and set aside. Remove the heads on the okra and then slice them into two, lengthwise. Cut the tomatoes into quarter wedges,
On a hot non-stick pan over medium heat, add some olive oil and pan sear the fish steaks for about 5 minutes (or until golden brown) on each side. Place the steaks on a baking tray. (Do not discard the fish marinade we will use it on the veggies).
Meanwhile, place another pan over medium heat. Add 1 tablespoon of olive oil, throw in some snow peas and sauté. Add the okra and continue to sauté. Add some salt to taste.
Add half a cup of water and bring to a simmer until the vegetables are half cooked. Pour the veggies on the same baking tray with the fish. Place the tomatoes on the tray as well and sprinkle the fish marinade over the veggies.
Bake in oven at 200°C for about 25 to 30 minutes. Once ready, serve the juicy tuna steak and veggies as a meal on its own.