To make simple syrup, mix sugar and water in 1-quart saucepan. Heat to boiling over medium-high heat, stirring until sugar is dissolved. Remove from heat and set aside to cool, about 1 hour. Pour syrup into glass jar, cover jar and refrigerate until needed. 1 1/4 cups (use 1 tablespoon per margarita).
To prepare cocktail, add cranberry juice, tequila, orange-flavored liqueur, simple syrup and lemon juice to cocktail shaker filled with ice. Cover and shake. Rub rim of martini glass with lemon wedge; dip in sugar. Strain cocktail into glass.