Heat the microwave rice according to packet directions. Divide the hot rice between two bowls.
Place the drained tuna in a small bowl. Gently flake with a fork.
Add mayonnaise, soy sauce, and sesame oil to the tuna. Mix until creamy and combined.
Spoon the tuna mixture over the hot rice.
Scatter sliced green onions over the top and add chilli oil or chilli flakes if you like heat. Add any additional toppings of your choice Serve immediately.