Combine the tequila, lime juice, agave nectar, maraschino liqueur and cherries in a blender and blend a few times to coarsely chop the cherries.
Fill a cocktail shaker with ice. Pour the cherry mixture into the shaker and shake well.
Put a scoop of sorbet into 4 margarita glasses. Strain the cherry mixture over the top. Add a splash of club soda and garnish with fresh cherries and mint sprigs.