Combine the garlic and shallot in a food processor and process until a paste forms. Place in a large bowl, add the soy sauce, rice wine, and sugar and stir to combine. Add the pork, cover, and marinate in the refrigerator for 6 hours or overnight.
Preheat the broiler or fire up the grill. Take the pork from the marinade and place it in a clean bowl. Reserve the marinade. Add the oil to the pork, stir, then thread the pork onto skewers, 5 or 6 pieces per skewer. Grill or broil for about 5 minutes on each side, basting with the marinade, until the pork pieces carmelize.