Place peppers, garlic, and salt in a food processor; pulse until finely chopped. With the motor running, slowly pour vinegar through the feed tube; process until smooth, about 5 minutes.

Pour sauce into a medium saucepan and bring to a boil over medium-high heat; cook for 1 minute. Remove from heat and let cool. Transfer to a jar; refrigerate for at least 1 day.

Strain sauce through a fine-mesh strainer. Store refrigerated.