Cook 350g of pasta shells in salted boiling water according to the package directions. Add 200g of trimmed chopped green beans for the final 3 minutes, cooking until both are tender.
Meanwhile, flake 200g of canned tuna in oil into a large bowl, including its oil. Add the finely grated zest of 1 lemon, 1 heaping tablespoon of capers, and 1 generous pinch of chili flakes.
Drain the pasta and beans, then toss with the tuna mixture. Season with salt and black pepper. Add a little olive oil if dry.
