Soak the hickory chips in water for 30 minutes, and then drain. Place the soaked chips in a stovetop smoker or outdoor smoker over medium-high heat. Peel and quarter the onions and place in a perforated pan. Cover with tin foil, poke a few holes in it, place in the smoker, and smoke for 1 hour. Your onions should be soft and have a nice brown color. Tasting the onions for smoke flavor is the best way to check for doneness, not all smokers are the same. When the onions are smoked, transfer to a food processor and puree until smooth. Cool. Combine with the rest of the ingredients. Mix well and taste for salt.