In a blender, combine raspberries, lime juice, and sugar (you may need to do this in batches). Whirl until puréed. Rub purée through a fine strainer set over a glass measure; discard seeds. Stir in tequila and triple sec.
Put half of the crushed ice into the blender with half of the raspberry mixture. Whirl until blended. Repeat with remaining ice and raspberry mix.
If desired, rub rims of 8 glasses (8 oz. or smaller) with lime wedge. Pour a thin layer of sugar into a shallow dish; dip glass rims into sugar. Pour margaritas into glasses and serve cold.
Note: Nutritional analysis is per serving.