Prepare the tilapia by cleaning and scaling it thoroughly.
Make two to three small diagonal slits on each side of the fish so the seasoning goes in deeper.
Rub the fish with salt and pepper, making sure to include the cavity.
Prepare the stuffing by mixing sliced tomato, half of the onion, minced garlic, and half of the ginger in a small bowl.
Season the stuffing with a bit more salt and pepper, then mix everything well.
Place the stuffing inside the cavity of the tilapia.
Add the remaining tomato, onion, garlic, and ginger slices on top of the fish for extra flavor.
Place the stuffed fish on a sheet of aluminum foil and wrap it tightly to seal in the juices.
Put the wrapped tilapia in a steamer basket and set it over boiling water.
Steam the fish for 25 to 30 minutes, or until it flakes easily with a fork and is fully cooked.
Carefully unwrap the foil, transfer the tilapia to a serving plate, and serve it hot with rice and dipping sauce.