Cook pasta according to package instructions. While boiling pasta, heat 1 tbsp olive oil over medium heat in a large pan. Add red onion and cook for about 2 minutes. Add asparagus pieces and saute for another 5 minutes or until desired doneness. Add tomatoes and allow to cook for about a minute.
Strain pasta and stir in mozzarella pearls and vegetables. Season with salt and pepper. Top with chopped parsley and drizzle with olive oil to serve.