Heat the oil in a small saucepan over medium heat. Add the chopped bell pepper, hot peppers, and garlic. Sauté for 3–4 minutes, until the peppers soften slightly. Stir in the vinegar, sugar, and salt. Bring to a boil, then reduce to a brisk simmer and cook for 8–10 minutes, stirring occasionally, until the mixture turns glossy and syrupy enough to coat the back of a spoon. Remove from heat and cool for 5–10 minutes.
The glaze will thicken as it cools and can be stored in a sealed jar in the refrigerator for up to 2 weeks.