Bring a large pot of salted water to a boil and cook the cheese tortellini according to package instructions until tender.
Drain the tortellini and rinse gently under cold water until completely cooled to stop the cooking process.
Transfer the cooled tortellini to a large mixing bowl.
Add the fresh spinach, cherry tomatoes, mozzarella cubes, black olives, red onion, and sun-dried tomatoes to the bowl.
In a small bowl or jar, whisk together olive oil, red wine vinegar, Italian seasoning, garlic, Dijon mustard, salt, and black pepper until smooth and well combined.
Pour the dressing over the tortellini mixture and toss gently until everything is evenly coated.
Sprinkle fresh parsley over the salad and mix lightly once more.
Cover and refrigerate the salad for at least 30 minutes before serving so the flavors can blend together.
Toss again before serving and add extra dressing or fresh herbs if desired.