Make the dressing by combining mayo, sour cream, garlic, and rice vinegar. Set aside.
Chop pumpkin seeds into smaller pieces. Set aside.
Peel (I just use a potato peeler) the carrots and then use a grater or food processor to shred them. In a bowl, mix the shredded carrots, dressing, and pumpkin seeds. Add salt and pepper if desired. Serve immediately.