1/2 cup harissa sauce
2 tablespoons white-wine vinegar (or more)
1/8 teaspoon cayenne (or more)
Kosher salt to taste
In a small bowl, whisk together harissa sauce, 2 tbsp. white-wine vinegar, and 2 tbsp. water. Add cayenne (or more) and salt if it needs it.
Make ahead: Up to 3 days, chilled.