You can be sure that if you walk into Philip Ward’s Mayahuel this Cinco de Mayo, you’ll get a classic margarita made with an ounce of Cointreau, three quarter ounces of fresh lime juice, and two ounces of tequila (Ward’s affordable favorites: Herradura Silver, El Tesoro, and Siete Leguas). But what if you want to celebrate outdoors — in the margarita-mad West Village? We recently took Ward on a tour of several Mexican favorites with alfresco seating and had him rank their margs — on the rocks with salt, bartender’s pick of poison. Brace yourself — there are a few surprises here (we’re looking at Dos Caminos Soho’s $15 special).