Finely chop the onion and tuna.
Remove excess moisture from the tofu with a paper towel, then cut into bite-sized pieces.
Heat olive oil in a pan and sauté the onion.
When the onion becomes translucent, add the tuna and stir-fry together.
Add the tofu to the pan and season with salt and pepper.
Once all ingredients are well mixed, transfer to a serving dish.