Made of soft, supple salmon; crisp lettuces and vegetables; and a very savory dressing run through with chiles and lime, this light salad is tangy and full of flavor. The dressing, based on nuoc cham, a traditional Vietnamese dipping sauce, has just enough fish sauce to give it depth and pungency without overpowering the brightness of the lime. You can substitute other fish, or even chicken, for the salmon. Just adjust the grilling time as needed, and toss with the dressing while still warm. Note that if you don’t have a grill, you can roast the fish in the oven.