1. Combine first 3 ingredients and 1 sliced garlic clove in a food processor or blender; pulse until coarsely chopped. Add lemon juice and 2 tablespoons olive oil, and pulse to form a thick paste. Season to taste with kosher salt and black pepper. Set aside.
2. Prepare pasta according to package directions. Cover and keep warm.
3. Meanwhile, heat remaining 2 tablespoons olive oil in a skillet over medium-high heat. Add remaining 2 garlic cloves; cook 1 minute. Add tomatoes and kosher salt and black pepper to taste; cook 3 to 5 minutes or until tomatoes are tender but hold their shape.
4. Toss hot pasta with reserved arugula pesto. Top with mozzarella, and serve with sautéed tomatoes.