Homemade tortillas are fabulous party food. The pork belly can be prepared and marinated ahead of time. I suggest cooking it the day before, so on the day it just needs reheating.
In a small bowl combine garlic, chilli, cumin, oil, salt and lemon juice. Remove skin from the pork belly. Rub the meat with marinade and leave for at least 4 hours or overnight.
Preheat a barbecue to low. Remove the pork reserving the marinade for basting. Cook pork, covered, on hot plate for 2 hours, turning once every 30 minutes. If you find it getting too dark, place it on a sheet of tinfoil.
While it is cooking make tomato salsa and guacamole. When the pork is cooked and tender let it sit for 10 minutes.
Heat tortilla on barbecue for 30 seconds each side.
Serve the pork sliced on the tortilla with a dollop each of tomato salsa and guacamole. Garnish with coriander.
To make tomato salsa: Combine all ingredients with salt and pepper to taste.
To make guacamole: Mash all ingredients with salt and pepper to taste.