Drain canned tomatillos and rinse briefly under cold water to remove tinny flavor and excess brine. Pat dry.
Roast tomatillos, chili, and garlic in a dry, hot pan for 4–6 minutes until charred and slightly softened.
Crush salt and garlic into a paste using a mortar and pestle (or blend).
Add chili and crush/blend coarsely.
Add tomatillos one at a time and crush/blend to your preferred consistency.
Stir in onion and coriander.
Season with lime juice and adjust salt if needed.
Serve with tacos, chips, grilled fish, chicken, or vegetables. Keeps for 2–3 days in the fridge.