First, prepare the pesto. Using a blender or food processor, purée the sun-dried tomatoes, pine nuts, sunflower seeds, Parmesan, garlic, and olive oil until smooth. Season with salt and pepper. Let the pesto sit for a bit.
Cook the pasta in plenty of salted water until al dente, drain, and reserve some of the pasta water. Let the pasta cool.
Halve the cherry tomatoes, roughly chop the arugula, and drain the mozzarella balls well.
Mix the cooled pasta with the pesto and possibly a little pasta water so that the pesto sticks well.
Add the mozzarella, tomatoes, and arugula just before serving so that they stay fresh and the mozzarella doesn't melt.
Season the salad with salt, pepper, and a little oil.
