Bring a large pot of salted water to a rolling boil over high heat. Add the pasta and cook until just al dente according to package directions, about 9 to 10 minutes.

While the pasta boils, place a wide skillet over medium heat and warm the olive oil. Add the sliced garlic, chopped fresh chilli, and dried chilli flakes, sizzling gently for 1 to 2 minutes until fragrant and golden.

Add the crushed tomatoes and capers to the skillet. Season with a light pinch of salt and black pepper, stirring well to combine. Allow the sauce to simmer for 5 to 6 minutes until slightly reduced and thickened.

Gently flake the drained tuna into chunky pieces and fold them into the tomato sauce. Simmer for 1 to 2 minutes just until the fish is warmed through without breaking it down completely.

Add the drained pasta and a small splash of the reserved cooking water directly into the sauce. Toss vigorously over medium-low heat until each piece is glossy and evenly coated, then turn off the heat and finish with lemon juice and fresh parsley.