Preheat oven to 225F. Line a baking sheet with aluminum foil, top with a wire rack and set aside.
Hold skin taught, and using a sharp knife patiently and carefully cut away excess fat from skin. Remove fat in stages until only a very thin layer remains. Set excess fat aside.
Rub baking soda into skin, then cut skin into 1 1/2 inch thick strips. Cut each strip into 1 1/2 inch squares.
Place squares fat side down on baking sheet. Transfer to oven and bake for 2 1/2 hours, until skin is crisp and golden on edges.
Meanwhile, roughy chop excess fat or pulse a few times in a food processor. Transfer to a dutch oven and turn to medium heat. Once the fat begins to render and sizzle, lower heat to lowest setting and leave uncovered. Stir every 10-15 minutes, and allow the fat to render for 2 1/2 hours. Afterwards, remove bits from pan until only melted lard remains.
Bring lard up to just below medium heat. Once lard ripples, add baked chicharrones in batches and fry up until crisp and fat layer puffs up, about 3-5 minutes. Drain on paper towels and repeat until all chicharrones are fried.
In a pinch bowl combine spices. Sprinkle hot chicharrones with spice mixture and serve.