- Toast the bread in a 200 °C oven after brushing it with olive oil.
- Mix red pesto with mayonnaise.
- Sear the tuna in a hot pan with olive oil for 40 seconds per side.
- Spread the pesto mayo on the toasted bread, then add sliced tuna, papaya sticks, caramelized onion, and mixed greens.
- Sprinkle with black pepper and serve.