In a 2 cup measuring cup, combine the sugar, lemon juice, and water and stir to dissolve the sugar. In the bender, combine the strawberries and sweetened water. Puree on high speed until smooth. Add the sparkling water and pulse to incorporate. Taste and add more sugar if desired, and pulse to incorporate. Place cracked ice in 2 tall Collins glasses. Pour the strawberry crush over the ice, garnish with mint sprigs, and serve.