Heat oil in a large saucepan over medium heat. When hot, add cumin, fennel and mustard seeds. Stir until mustard seeds pop, about one minute. Add onion and cook, stirring frequently, until beginning to brown. Add ginger and chile and continue to cook until softened. Add the vinegar–sugar mixture, water, cranberries, orange peel and salt. Simmer until the juices thicken, stirring often, about 20 minutes. Remove from heat and let cool.