When you first sit down at this longtime West Side fixture, your server will present you with a drinks menu that boasts a wide array of margarita choices. Bypass the foo-foo blue ones, the slushy blender versions, the yup-version made with Grand Marnier, and head straight for the la Señora ($4.25). This, boys and girls, is what God was thinking of when he invented the lime: Here it is fresh-squeezed with tequila and triple sec over ice in a cocktail shaker with a little strainer on top. There's enough potent, bracing margarita within to fill the salt-rimmed martini glass that will arrive alongside it--twice. And there's enough hooch in each glass that you probably won't need another round, although you'll want one. Need to settle a longstanding argument about the merits of Hornitos vs. Patron? If your constitution can bear it, Boca Chica also offers tequila samplers. Pucker up.