1. Preheat the oven at 200 degrees Drizzle a few drops of olive on ciabatta slices. Sprinkle some and season with salt and pepper.
2. Broil or toast the slices in preheated oven for 7-8 minutes or until golden and crisp Meanwhile, 2 tablespoons (30 ml) of olive oil in a pan. Add garlic and toss for a few seconds.
3. Add onions and toss for a minute or until just pink.
4. Add mushroom slices and toss on high for 2 - 3 minutes. Season with salt and pepper, toss again for a minute. Take it off the heat, make sure that no water remains and mixture is dry.
5. In a bowl, add tossed mushroom, tuna flakes, Del Monte Tartare Mayo Dip, lemon juice, black olives, cherry tomatoes, and mix well.
6. Take the slices of Ciabatta and layer it with bed of red romaine lettuce, Top it with prepared sandwich mixture and rocket leaves.
7. Place them on a serving platter and serve.

Enjoy your meal!