1. Combine milk and buttermilk in a small heavy saucepan over medium heat; bring to a boil, stirring occasionally. Remove from heat; drain. Place milk solids in a small bowl; sprinkle with 1/8 teaspoon salt. Toss gently to combine.
2. Bring 6 quarts water to a boil in a large Dutch oven. Stir in 1 tablespoon salt and pasta; cook 7 minutes or until al dente. Drain.
3. Heat a large nonstick skillet over medium-high heat. Add oil to pan; swirl to coat. Add zucchini; sauté 2 minutes, stirring occasionally. Stir in 1/4 teaspoon salt, pepper, and garlic; sauté 2 minutes, stirring frequently; stir in tomatoes. Combine remaining 1/8 teaspoon salt, pasta, and tomato mixture in a large bowl; toss. Top with ricotta and mint.