For the dressing: In a small mixing bowl, whisk together the garlic, mayonnaise, chili sauce, ketchup, onion, and relish until combined. Season with salt and pepper to taste. Cover and let sit for about 30 minutes so the flavors blend. (You can store covered in the refrigerator for up to 2 days.)
Arrange the salad ingredients decoratively on a low-line platter or bowl. Serve with the chilled dressing on the side, with extra lemon wedges.