For dressing, in a blender container or food processor bowl cover and blend or process raspberries till smooth; strain through a sieve to remove seeds. Discard seeds.
In a medium saucepan combine sugar and cornstarch; stir in strained raspberries, the berry drink, vinegar, celery seeds, cinnamon, and cloves. Cook and stir over medium heat until thickened and bubbly; cook and stir for 2 minutes more. Transfer to nonmetal container. Cover and chill at least 1 hour.
To serve, in a salad bowl toss together spinach, walnuts, dried cranberries, sunflower seeds, and green onions. Drizzle with half of the dressing. (Cover and chill remaining dressing in a nonmetal container for up to a week to use in other vegetable or fruit salads.)