Heat oven to 350°F Sprinkle pears with cinnamon and place, cut side up, in a baking dish. Place 1 piece of margarine in the core cavity of each pear. Add water to dish and bake pears until tender, about 1 hour, basting with water one halfway through. Remove from oven and cool slightly. Slice each pear lengthwise into thin slices and fan out on dessert plates.
Heat chocolate and half-and-half in a small saucepan over medium-low heat, stirring constantly, until melted and well combined, 1 to 2 minutes. Using a large spoon, drizzle chocolate sauce decoratively over pear slices. Sprinkle with pomegranate seeds and serve.