Makes 2 cups
Spread the sesame seeds, coriander seeds, cumin seeds, and flaxseeds on a dehydrator tray lined with a nonstick dehydrator sheet and dehydrate at 118°F until fragrant, 3 to 4 hours.
Grind the dehydrated spices in a spice grinder until fine, then transfer to a food processor. Add the walnuts, coconut palm sugar, salt, and pepper and pulse until the mixture looks like coarse sand, being careful not to overprocess the nuts into a paste, 20 to 25 pulses.
Transfer to an airtight container and store in a cool, dry place for up to 1 month.