In a blender, whirl the peaches to a smoothed puree. This should yield about 1/3 cup of puree (5oz).
Place enough salt in a shallow, wide dish to make a mound. Run one of the lime wedges around the rim of a chilled margarita or cocktail glass. Holding the glass sideways by the stem and roll it in the salt to coat the outside edge and rim. Set the glass aside.
Fill a chilled cocktail shaker with ice and add tequila, lime juice, Sweet'N Low®, and 1 ounce of the peach puree. Shake well. Strain the drink into the prepared margarita or cocktail glass. Add half of the ice from the shaker. Garnish with the remaining lime wedge.