To make the gremolata, combine the capers, parsley, cup of rocket, lemon zest and juice and ¼ cup of the oil in a small food processor and process until finely chopped. Season and refrigerate until ready to use.
Heat remaining oil in a large non-stick frying pan over medium heat. Add the garlic and bread and cook, stirring occasionally, for 4-6 minutes or until golden. Set aside.
Cook the pasta in salted boiling water for 6-8 minutes or until al dente. Drain, reserving ½ cup of cooking water. Return the pasta to the saucepan with the cooking water, gremolata and tuna, and toss to combine.
Divide between bowls, serve with rocket and crunchy breadcrumbs.
