In a large skillet heat olive oil and genlty saute finely minced garlic and onion for about 5 minutes until soft and golden. Add seasonings and saute another 2-3 minutes.
Strain canned tomatoes through a sieve reserving liquid and discarding any tomato pieces. You could also puree the tomatoes in a blender or food processor. Add tomato liquid to the pan with the onions and bring to a boi; reduce heat and simmer for 10 minutes to thicken. Add shrimp and scallops to the tomato sauce, cover and let cook 3-4 minutes. Stir in heavy cream, increase heat slightly and simmer another couple of minutes.
Serve over capellini sprinkled with parsley and parmesan cheese.