Saute onion and garlic in oil for 5 to 7 minutes.
Combine the wild greens, shrimp, half the provolone and mozzarella cheeses, bread crumbs, Romano cheese, thyme, salt and pepper in a food processor and chop to mix. Place in a large bowl and stir in cooked onion and garlic.
Spoon this filling into cooked pasta shells and place in a 9" x 13" baking dish. Pour spaghetti sauce over shells and cover with foil to bake. Place in 350F oven for 20 minutes. Remove foil and sprinkle with remaining cheeses. Bake 10 minutes more, or until cheese is melted and sauce bubbles.