I'm not Italian but I did live in Italy three years. Roasting skin-on pork belly that's been wrapped around a pork loin gives the best results IMHO.
1. Set belly skin side down. Using a knife, score the belly flesh in a checkerboard pattern 1/3" deep so roast will cook evenly.
2. Flip belly skin side up. Using a paring knife, poke dozens of 1/8"-deep holes through skin all over belly. Don't be gentle! Keep poking.
3. Using the jagged edge of a meat mallet, pound skin all over for 3 minutes to tenderize, which will help make skin crispy when roasted.
4. Turn belly and generously salt both it and loin; Season with garlic and fresh herbs and spices to your taste. Arrange loin down middle of belly. Top with orange slices.
5. From the narrow end, roll tightly toward the broad end, tie crosswise with kitchen twine at 1/2" intervals. Trim twine.
6. Cook direct searing outside then cook indirect ~20 mins per lb until 145*.
I've used this method which is a compilation of various methods found on the internet. Food Network's Anne Burrell has a good one as well. I'd post the link but I'm not allowed to per the rule book.