Heat the cooking oil in a wok or sauté pan.
Saute the onion, garlic, and tomato.
Once the onion gets soft, add the squid. Cook for 2 minutes.
Put-in the fish sauce and water. Stir. Continue to cook for 3 to 5 minutes.
Add the ground black pepper and adjust the taste by adding more fish sauce, only if needed.
Transfer to a serving plate. Serve.
Share and enjoy!