Roast the red pepper over a gas flame or under the broiler until blackened on all sides. Remove from heat and seal in a paper bag and let stand for 10 minutes. Peel, seed and chop.
In a large bowl combine the vinegar, maple syrup, hot pepper sauce, ground turmeric and salt. Gradually whisk in the oil. Add the chopped red pepper, thawed corn and green onions. Toss to coat. Cover a refrigerate overnight, stirring occasionally. Can be made up to 3 days ahead of time. Let relish stand at room temperature for 30 minutes before serving.