In medium-size nonreactive saucepan, combine vinegar, the 1/2 cup sugar, the ginger, red onion, garlic and cayenne. Bring to a simmer; cook, uncovered, over medium heat for 10 minutes.
Add cranberries, pineapple with syrup, and salt. Return to simmer; cook, stirring occasionally, 15 minutes, until cranberries are softened.
Remove from heat. Stir in the remaining 1/4 cup sugar. Spoon into glass bowl; let cool completely. Cover with plastic wrap and refrigerate until ready to serve.