Salt or no salt? It's always a conundrum. Best to settle on a half-rim so that every gulp of margarita doesn't come with a mouthful of the stuff. Salt does great things to tequila and lime, but in small doses. Too often that gritty too- salty sensation smacks of overkill. Clearly the bartenders at the relocated-from-Crystal City Oyamel (401 7th St., NW, 202-628-1005) have thought about this. Because when you order a margarita at the always-crammed bar of this Jose Andres Mexican, no one asks about salt. They've got it covered. With foam. The Oyamel margarita comes with a cloud of lightly salted foam on top. No grit. No overkill. Just a perfect balance of the sweet, tart, and salty. The secret? Egg whites? A cappuccino foamer? I asked the bartender and found out it was simpler than all that.

Oyamel's Salt Air for Margaritas

1 cup fresh squeezed lime juice
2 cups water
1 tablespoon kosher salt
1/2 teaspoon soy lecithin (available at GNC stores)

Combine ingredients. Tilt the bowl away from you and blend with hand-held blender held in the far corner. When there's an inch or so of foam on top, it's ready to use. Skim off foam onto margarita (made with your favorite recipe). When you've used it all up, repeat the process. Juice mixture can be refrigerated for several days.