Season the pork with salt and pepper. Stir together the lemon juice, 2 grated garlic cloves, the oregano and 3 tablespoons olive oil in a small bowl. Remove 1 tablespoon of the mixture and set aside for topping; rub the rest all over the pork.
Make the dressing: Combine the yogurt, vinegar, half of the cheese, the scallion whites, 3 tablespoons dill, remaining 1 grated garlic clove, 3 tablespoons water, 1/2 teaspoon salt and a few grinds of pepper in a food processor. Puree until smooth, adding more water 1 teaspoon at a time to loosen if needed. Refrigerate until ready to serve.
Heat a large nonstick skillet over high heat. Add the remaining 1 tablespoon olive oil. Add the pork chops and cook until browned and cooked through, 4 to 5 minutes per side. Transfer to plates.
Divide the lettuce wedges among the plates and season with salt and pepper. Top the pork with the reserved 1 tablespoon lemon juice mixture. Spoon the yogurt dressing all over the lettuce. Sprinkle with the remaining cheese and dill and the scallion greens.