Heat skillet over medium high heat. Add olive oil and brussel sprouts, and cook 5 minutes, or until browned, stirring occasionally. Add shallots and garlic, and cook 1 minute more. Stir in ginger, cranberries and ¼ cup water. Reduce heat to medium, and simmer 5 to 7 minutes, or until most of liquid has evaporated and Brussels sprouts are just tender, but not soft. Add walnuts and season with salt and pepper.