Preheat the oven to 425 degrees F. Toss the tomatillos and onion pieces in a bowl with 1 teaspoon of the oil and a sprinkle of salt. Transfer the whole lot to a sheet pan, and roast in the oven until the vegetables blister and collapse, about 25 minutes.
Heat the remaining teaspoon of oil in a medium saucepan over medium-high heat and cook the jalapenos and poblanos until soft, about 3 minutes. Add the honey, vinegar, coriander, mustard, roasted vegetables and cilantro stems and bring to a simmer. Simmer until the sauce is slightly reduced and the roasted onions are very tender, about 20 minutes.
Transfer the sauce to a blender with the cilantro leaves and 2 teaspoons salt and blend until smooth. Stir in the tequila and season with more salt if desired. Use immediately, or refrigerate in a nonreactive container for up to 2 days.