First rehydrate the tomatoes. Place them in a bowl, a submerge in warm water. Let them soak for about 15 minutes, then drain.
Meanwhile, toast the walnuts. Preheat a small, heavy bottomed pan over medium heat. Toss in the walnuts and toast them, stirring often, for about 7 minutes. They should be varying shades of toasty brown, and smell walnut-y. Transfer immediately to the food processor.
Pulse the walnuts and fennel seed to finely chop. Add the remaining ingredients, except for the marjoram, and puree until relatively smooth. Add the marjoram and pulse a few times to get it integrated. Keep refrigerated in a tightly sealed container until ready to use.