Over low heat, in a medium-size skillet, lightly toast sesame seeds, fennel seeds, and spices. Allow cooling. Toasting releases the essence of the seeds and spices.
Pound (dukkah means "to pound") the seeds with a mortar and pestle. Go for a coarse powder. Not chunky. Add the sea salt and crushed black pepper. Combine all of these ingredients.
Wipe out the skillet and over low heat, lightly toast the pistachios just to the point of a golden hue, but not brown. You want to just release the notes of the nuts. Allow cooling.
Pound the pistachios into coarse, rough sand. You don't want them to be a powder. You want to retain their character in a manner that will blend well with the other ingredients, yet also stand out on their own.
Now add pistachios to the first mixture. Store dukkah in an airtight container where it's cool. Nuts contain oils that can go rancid, so store no longer than 6 months or freeze for up to a year.