Almost like in ceviche, where the citrus juice cures the fish, the lemon and lime in this dressing soften the delicate ribbons of summer squash as the salad rests. Look for zucchini and yellow squash between 6 and 8 inches in length; avoid the really big ones, as they tend to be pithy. If you can’t find both varieties of squash, just one kind works as well. You’ll want to carefully slice them into long, thin ribbons; a mandolin or potato peeler works best, or you can use a very sharp knife, depending on your knife skills. I like to use a platter instead of a salad bowl to give the squash ribbons the most amount of surface in contact with the dressing. You can add more color and flavor to the salad with slivers of jamón serrano or burrata scattered about, but I love it as it is, served …