Bring 4 quarts of water to a rolling boil in a large pot (for pasta).
While water comes to a boil, heat the oil, about 1/2 of the garlic, red pepper flakes and capers in a 12-inch skillet, and stir frequently until mixture is fragrant and sizzling, but not browned, about 1 to 2 minutes.
Add the wine and simmer for about 1 more minute; add the tuna and 2 teaspoons salt and cook, stirring frequently, until the tuna is heated through - about 1 minute.
When water is boiling, add 1 tablespoon salt and the pasta; cook until al dente and drain, reserving 1/4 cup of the cooking water.
Return the pasta to the pot and toss with the tuna mixture, the rest of the garlic, parsley, lemon zest, butter and reserved pasta water.
Season with ground black pepper and salt to taste; top with freshly grated parmesan cheese.