1. Preheat oven to 350°F; grease an 8-inch square dish. Cook ziti in boiling, salted water until almost al dente, about 7 minutes. Drain and rinse with cold water.
2. Warm 2 Tbsp. oil in a large skillet over medium-high heat. Add onion; sauté until softened, about 3 minutes. Add garlic; sauté 1 minute. Stir in turkey and sauté 1 minute. Mix in tomatoes and season with salt and pepper. Simmer, stirring, until thick, about 10 minutes.
3. Combine ricotta, 1 cup mozzarella, 1/4 cup Parmesan and pesto in a bowl; season with salt and pepper. Spread 1/2 of ziti in dish; top with 1/3 of sauce. Spread with ricotta mixture and cover with remaining ziti and sauce. Sprinkle with remaining cheese; drizzle with 1 Tbsp. oil. Bake until bubbly, about 30 minutes.