Bring a medium pot of heavily salted water to a boil over high heat. Cook pasta according to the package directions, or until al dente. Drain, then rinse under cold water until cool.
Transfer pasta to a large bowl and add mozzarella, spinach, olives, and Parmesan. Toss to combine.
In a separate, nonreactive bowl, combine vinegar, salt, and pepper. While whisking constantly, slowly add oil by pouring in a thin stream down the side of the bowl. Whisk until completely incorporated.
Pour vinaigrette over salad and toss until pasta is coated. Taste, adjust seasoning as desired, and serve.