Cook the pasta sheets, in batches, in a large saucepan of salted boiling water according to the packet instructions until just al dente. Drain and return to the pan to keep warm.
Meanwhile, heat the oil in a frying pan over a medium heat, add the spring onions and courgettes and cook, stirring, for 3 minutes. Remove from the heat, add the tomatoes, tuna and rocket and gently toss together.
Place a little of the tuna mixture on 4 serving plates and top with a pasta sheet. Spoon over the remaining tuna mixture, then top with the remaining pasta sheets. Season with plenty of pepper and top with a spoonful of pesto and some basil leaves before serving.