1. Preheat the oven to 350°F (180°C).
2. Wash the zucchini and cut them into small cubes. Wash the bell pepper, remove the seeds, and cut it into small cubes.
3. In a pan, sauté the vegetable cubes in boiling olive oil for 10 minutes. Season and set aside.
4. Drain the tuna and crumble it with a fork.
5. Break the eggs into a bowl and whisk them.
6. Add the flour, baking powder, and milk while continuing to stir vigorously. Add the zucchini, bell pepper, and tuna mixture. Lightly season with pepper.
7. Line a loaf pan with parchment paper and pour in the batter.
8. Bake for 45 minutes.
9. Wash, dry, and finely chop the chives.
10. Serve warm or cold, garnished with chives.