Bring a large pot of salted water to a boil. Cook 12 ounces of spaghetti or bucatini until just shy of al dente according to package instructions. Reserve 1/2 cup of pasta water before draining.
In a large skillet over medium heat, warm 2 tablespoons of olive oil. Add 2 minced anchovy fillets and cook, stirring, for about 1 minute until melted into the oil.
Add 1 finely chopped shallot and sauté for 3–4 minutes, until soft and translucent. Stir in 1 teaspoon Calabrian chili paste and 2 tablespoons tomato paste. Cook for another 2 minutes, letting the paste darken slightly.
Pour in 1/4 cup dry white wine and scrape up any bits stuck to the bottom. Stir in 1 (14-ounce) can of crushed tomatoes, 1/2 teaspoon kosher salt, and 1/4 teaspoon black pepper. Simmer over medium-low heat for 10–12 minutes, stirring occasionally.
Add the drained pasta directly into the sauce. Toss gently, adding a splash or two of reserved pasta water as needed to loosen and coat the pasta. Cook together for 1–2 minutes until glossy and well combined.
Turn off the heat. Gently fold in the drained tuna in large flakes. Do not stir too much—you want big, visible pieces. Add 1 tablespoon fresh thyme leaves and the zest of 1 lemon.
Divide into bowls and serve immediately. Optional: drizzle with a little olive oil or add more chili paste if you like extra heat.