Make the syrup. In a small saucepan, combine the cranberries, water and sugar. Bring to a boil, then simmer over medium heat until all cranberries have burst open. In a blender, combine the chiles, orange zest and cranberry mixture. Cover loosely and blend until very smooth. Strain into a bowl or small pitcher and refrigerate until cold.
Make the cocktail. Rub the rim of a 5-ounce cocktail glass with a lime wedge, then upend the glass in the salt spread on a small plate. Fill a shaker about ½ full with ice cubes, then measure in the mezcal (or tequila), the orange liqueur, Cranberry-Chipotle Syrup and lime juice. Secure the top and shake vigorously for about 15 seconds. Strain into the prepared glass and enjoy!