Preheat your oven to 425°F and grab a large roasting pan (around 11-by-15 inches).
Add the tomatoes, olive oil, tomato paste, lemon zest strips, cinnamon sticks, dried ancho chiles, garlic head (cut-side down), and oregano sprigs to the roasting pan. Season generously with 1½ teaspoons salt and ¼ teaspoon pepper. Arrange in an even layer, ensuring the chiles are tucked beneath the tomatoes.
Slide the pan into the oven and roast for 35 minutes, or until the tomatoes are tender and lightly charred. Once done, use tongs to gently squeeze the roasted garlic cloves out of their skins into the pan. Discard the skins.
Finely chop the ancho chiles, discarding their stems, and stir them back into the roasted tomato mixture.
Meanwhile, cook the rigatoni in a large pot of salted boiling water according to package instructions. Reserve ⅓ cup of pasta water before draining.
Add the cooked rigatoni to the roasted tomato pan, gently stirring to coat. Gradually add reserved pasta water until the sauce clings smoothly to the pasta.
Remove the cinnamon sticks and garnish with fresh oregano. Serve warm.