Cook pasta per package directions and then drain, saving ½ cup of cooking water.While the pasta cooks, drain tuna, saving 3 tablespoons of the oil.
Combine the tuna, reserved oil, lemon juice, anchovies and dried chilli flakes in a blender or food processor and process until smooth.
In a large bowl, toss the hot drained pasta with tuna sauce (thinned with pasta water if necessary), rocket, lemon zest and salt and pepper to taste.
Serve topped with grated Parmesan and plenty of freshly ground pepper.
