Bring a large pot of heavily salted water to a rolling boil over high heat. Add the pasta and cook for 2 minutes less than the package suggests. Reserve about 500ml (2 cups) of pasta cooking water before draining.
While the pasta is cooking, add 2 tbsp of sun-dried tomato oil to a large skillet. Add the garlic, chili flakes and anchovy fillets if using. Set over medium heat and, stirring occasionally, gently cook until the garlic is tender and the anchovies begin to dissolve - about 5 minutes.
Add the sun-dried tomatoes, artichokes, tomato paste, oregano and a generous grind of black pepper. Cook for a minute or two, just until the tomato paste darkens and begins to stick to the bottom of the pan.
Pour in 250ml (1 cup) of pasta cooking water into the pan, stirring to thoroughly combine. Stirring constantly, sprinkle in the parmesan cheese until incorporated and emulsified.
Add the cooked pasta and toss to coat in the sauce, adding more pasta cooking water where needed to achieve your desired sauce consistency. If using, break up the tuna with a fork and add it to the pasta, stirring to combine. Taste to adjust for seasoning, adding salt and pepper where needed, and serve immediately.