Make the sugared cranberries: Combine ¼ cup of sugar and ¼ cup of water in a medium saucepan over medium heat. Bring to a simmer, and stir until the sugar is dissolved, about 2 minutes. Remove from heat, and add in the cranberries. Stir until well coated. Allow to sit for 10 minutes*, then using a slotted spoon, transfer the cranberries to a wire rack*. Set aside and allow them to dry for at least 1 hour.
Once dry, add the remaining 1/2 cup of sugar to a large plate. Roll the cranberries in sugar until well coated. Allow to dry again, for at least another hour.
Serve: Strain margarita over ice filled glass rimmed with sugar and salt*. Garnish with sugared cranberries and other optional garnishes if using. Enjoy!
*Yield: about 3 cups