Preheat oven to 450ºF (230ºC).
Grind the fennel seeds in a mortar and pestle with the rock salt.
Rub the mixture into the pork skin, getting it deep into the cuts.
Place the pork, skin up, in a roasting pan.
Drizzle oil over the rind.
Rub the salt mixture over the rind and into the cuts.
Roast for 45 minutes or until the rind crackles.
Reduce oven temperature to 400ºF (200ºC).
Add in your choice of vegetables and roast for another 1 hour or until pork is cooked through.
Remove from the oven, cover with foil, and rest for 10 minutes before serving.