1. Open the can of pears; pour the pear juice into a container and place it in the fridge. 

2. Place the pear slices in a freezer-safe container and place in the freezer for 4-6 hours, until frozen.  Remove the pears from the freezer and set them on the counter for about 15 minutes to thaw slightly. 

3. Place 2-3 slices of the frozen pear in a blender, then add the tequila, Ginger liqueur, pear juice, and lemon juice.  Blend until smooth. 

4. Mix the sugar, cinnamon, and margarita salt on a plate. 

5. Run a piece of lemon around the rim of a 10 oz glass, then dip the rim of the glass into the cinnamon sugar/salt mixture. 

6. Carefully pour the frozen pear margarita mixture into the glass.  Garnish with a fresh pear slice speared with a rosemary sprig.