Cook the pasta in boiling water with 1 tbsp salt. It should be al dente (about 7-8 minutes) and drain.
In the meantime, in a large skillet, heat the oil over medium low heat and sauté the garlic, anchovies, chili pepper flakes and continue to cook for another minute or so, just until you get that wonderful garlic aroma and the anchovies begin to “melt”. Add the tuna, capers, tomatoes, tapenade and lemon zest and sauté for 5 minutes. The grape tomatoes will be intact but hot and juicy when you bite into them.
Add the drained pasta to the sauce and toss well.