Remove and discard the stems from the chiles, and deseed half. Coarsely chop the chiles. Place in a blender along with the salt, and process until it becomes a semi-smooth mixture—still with some texture. Transfer to a saucepan and bring to a simmer over medium heat. Cook until the peppers soften a bit, 4 to 5 minutes.

Remove the pan from the heat and stir in the vinegar and water. Cool to room temperature, then transfer to clean jars with tight-fitting lids. Top with a bit of olive oil, if desired, then refrigerate the pepper sauce until ready to use; it will keep up to several months.