For the Mexican simple syrup: Bring the sugar, cinnamon sticks and 1 cup water to a boil in a small pot and cook for 2 minutes. Turn off the heat, then allow to cool to room temperature. Strain. (Makes approximately 1 cup.)
For the red hot ice cubes: Add the cinnamon candies, sugar and 1/2 cup water to a small saucepan over low heat. Cook until completely melted, then pour over ice cubes in a small rimmed baking sheet and freeze, stirring and scraping up the ice every 30 minutes, until completely frozen.
For the rim: Combine the salt, sugar, cinnamon and chile-lime seasoning in a shallow dish. Set aside.
For the margarita: Add 3 ounces Mexican simple syrup to a cocktail shaker, then add the lime juice, orange juice, tequila and a pinch of salt. Add plain ice cubes, then cover and shake.
Rub the cut side of the lime half along the rims of 4 rocks glasses, then dip the glasses into the rim mixture. Fill with the red hot ice. Strain the margarita into the glasses. Garnish with orange slices and serve.