Marinate the pork chops
Season the pork chops with salt. In a shallow glass or ceramic dish, whisk the romesco with 1 tablespoon of the oil. Add the chops, turn to coat, and let stand at room temperature for up to 1 hour.
Make the potato salad
Meanwhile, bring a saucepan of water to a boil over high heat. Add 1 tablespoon salt and the potatoes. Cook until the potatoes are tender, about 25 minutes. Drain, rinse under cold running water, and let cool slightly. In a large bowl, whisk together the remaining 5 tablespoons (2½ fl oz/75 ml) oil and the vinegar. Slice the potatoes and transfer to the bowl. Add the green onions and mix gently. Season with salt and pepper.
Grill the pork chops
Prepare a gas or charcoal grill for indirect-heat grilling over high heat. If using a gas grill, preheat using all of the burners, then turn off the burner directly below where the chops will sit. For a charcoal grill, arrange the hot coals on either side of the grill. Lightly oil the grill rack. Place the chops on the cooler area of the grill, cover, and cook for 5 minutes. Turn and cook until the chops feel firm when pressed, about 5 minutes longer. Serve with the potato salad.