How to Make It
Preheat the broiler. In a medium bowl, whisk the 3 tablespoons of olive oil with the red wine vinegar and Dijon mustard until combined. Add the flaked tuna, chopped artichokes, chopped olives, sliced red onion and shredded basil and toss gently. Season lightly with salt and pepper.
Using a pastry brush, brush the cut sides of the ciabatta lightly with olive oil and broil cut side up on a baking sheet for 2 minutes, until the ciabatta is golden and lightly toasted; shift the baking sheet for even browning. Rub the garlic clove over the toasted ciabatta and mound the tuna salad on top. Cover with the sliced Robiola cheese and broil until the cheese is just melted, about 1 minute. Serve the tuna melts at once.