Cook Spaghetti (450 gram) until al dente per package's instructions. Drain and set aside.
Roughly chop the Onion (1) and Garlic (6 clove). Halve the Pimento Stuffed Green Olives (1 1/4 cup). Reserve a 1/4 cup of the olives for garnish later.
Heat Olive Oil (1/4 cup) in large saute pan and add chopped onions. Cook until onions start to soften, about 5 minutes.
Add the 1 cup olives and garlic. Cook for another 2 mins.
Add the Canned Diced Tomatoes (14.5 ounce). And stir everything together. Bring to simmer.
Drain the Tuna Chunks (95 gram) and add them to the pan. Simmer for 2 minutes until the tuna is heated and the tomatoes have started to melt.
Transfer mixture to a blender. Season with Salt and Pepper (to taste).
Puree until smooth. Wipe out saute pan and return to low heat. Add pureed sauce and cooked spaghetti pasta. Toss to coat.
To serve, top the pasta with the remaining pimento stuffed green olives.