Transform raw onions into a sweet-tart, mellow topping for tacos, salads, and more. Serious Eats / Amanda Suarez I've never met a pickled red onion I didn't like. Tangy, tart, and vibrantly magenta, these tender alliums make a zippy topping for tacos , cheesy pizza , and even potato salad —worlds better than the harsh, pungent snap of raw onion. But the word "pickle" conjures images of lengthy pickling processes—even "quick" pickles, where a vinegary brine is poured hot over a vegetable and left to soak for several hours, require more time than I often have. We've covered "rapid" pickled onions on Serious Eats before—Daniel has written about how effective a brief soak in vinegar can be and included them in many of his recipes over the years. This variant, which we learned from chef and food stylist Julian Hensarling, swaps the vinegar with lime juice for an even fresher, brighter pop of flavor. It's a version he learned while living in La Paz, Mexico (where he ate his body weight in tacos).…