There are dresses and then there re dresses. This is one of the very special ones. Designed as a classic Mexican-inspired peasant dress, this has a ruffled, elasticized neckline with front vent and drawstring; you can wear it on your shoulders to create a scoop neck or, if the occasion warrants it, wear it off-shoulder and watch the little beads of sweat build up on his brow, long sleeves. The waist is defined by a broad swath of elasticized smocking followed by three gloriously full and…