Heat a large Carbon Steel Frying Pan or Griddle over medium-high until hot.

Add chiles and toast 1–2 minutes. Add whole tomatoes, tomatillos, and onion cut-side down to hot Pan. Turn occasionally until blistered and charred on all sides, 4–6 minutes. Remove and let cool slightly. Using a Chef Knife, quarter tomatoes, tomatillos, and onion once cool enough to handle.

Add cilantro, chiles, tomatoes, tomatillos, and onion to a high-speed blender or food processor and blend until smooth.

Add lime juice while blade is spinning on low speed. Add salt. Taste and add more lime and/or salt, if desired. If salsa is too thick, add a little water to keep things moving. Once smooth, chill until serving or use immediately.