Finely chop tuna and zucchini.
Mince onion and garlic.
Heat oil in a pan and sauté the onion and garlic.
Add zucchini and stir-fry.
Add tuna and stir-fry together.
Season with soy sauce, sugar, and pepper.
Place the stir-fried ingredients over rice.
Top with a soft-boiled egg to finish.