Put the pork belly in a china or glass dish.
For the rub, peel and crush the garlic to a paste, stirring in the soy, dried chilli flakes, groundnut oil, salt and five-spice powder. Spread this paste over the skin and underside of the pork belly. Leave it to marinate for a good 4 hours, if not overnight.
When the pork has marinated, preheat the oven at 220C/425F/Gas 8. Place the pork in a roasting tin then cook, skin-side up, for about 20 minutes. Lower the heat to 200C/400F/Gas 6 and continue cooking for a further 40-50 minutes, or until the skin is dark and crisp. Leave for 10 minutes to rest, then carve.
Meanwhile, to make the peach salsa, trim and finely chop the spring onions, finely chop the chilli, peel, stone and finely chop the peach and halve the tomatoes. Mix gently then dress with the lime juice and the olive oil.
Serve the ribs with the peach salsa on the side.