In a pot bring water, sugar, orange zest, and cranberries to a boil. Reduce the heat to a simmer and cook until all of the cranberries have burst. Cool and strain off the liquid. Makes 4-4 1/2 cups of syrup.
Mix the cranberry syrup with the lime juice, tequila, orange liqueur, orange slices, and cranberries. Rub the rim of a glass with an orange and dip in the salt. Fill the glass with ice and pour in margarita mix. Garnish with an orange slice and cranberries.
For a single serving, make the syrup as directed and mix with the lime juice. In a salted glass with ice, pour 1 1/2 oz tequila, 1/2 oz orange liqueur, and fill with cranberry lime mix.