As near as I could tell, it's only Margarita Day here in the USA. A quick search on the South of the Border Internet didn't turn up anything about a Mexican Margarita day (Día Nacional de la Margarita). One site did say that since we're celebrating Margarita Day here, there's no reason for Mexicans to miss out.
This margarita used lime, Meyer lemon, Citronge, Jose Cuervo Tradicional Reposado Tequila (100% agave), with agave sweetener and ice. That's it. It worked well, although the Meyer lemons have less of a citrus bite than pure limes.