Mix shallot, chiles, garlic, vinegar, and salt in a small bowl and set aside for 10 minutes for vinegar to soften the flavors of the onion and garlic.
Stir in the fresh herbs to combine and then whisk in enough of the oil to coat all the ingredients and so that none of the ingredients are above the oil (1/2 to 3/4 cup). This way the oil preserves the fresh herbs for storing.