Place a medium saute pan over medium heat and add the oil. Add the onion and cook until translucent, about 2 minutes. Add the garlic and ginger and cook until fragrant, 45 to 60 seconds.
Add the ketchup, peach jam and peaches. Reduce heat to low and simmer until the sauce thickens, about 30 minutes, stirring occasionally. Add the vinegar and season with salt and pepper. Remove from the heat and set aside to cool.
Meanwhile, in a medium heatproof bowl, dissolve the brown sugar and kosher salt in boiling water, then stir in the ice cubes to cool. Add the pork chops, cover the bowl with plastic wrap and refrigerate about 30 minutes. Remove the pork chops from the brine, rinse them well and dry thoroughly with paper towels.
Pour half the barbecue sauce into a shallow baking dish; reserve remaining sauce. Add the pork chops, turning to coat both sides.
Prepare a medium-hot grill or grill pan. Grill the chops until cooked through, about 5 minutes per side, basting chops with barbecue sauce. Remove from the grill and let stand 5 minutes before serving. Serve with the remaining sauce.