Prepare grill for direct/indirect cooking with lump charcoal. When coals hot, place 1/2 lemon over direct heat for 10 minutes, or until you see desired char marks. Then remove for dipping sauce.
After lemon is grilling for five minutes, preheat cast iron pan over direct heat with 1 tablespoon olive oil. The cast iron will take approximately 5 - 7 minutes to warm up.
In a medium size bowl toss remaining olive oil, peppers and 1/2 teaspoon salt. Place peppers into hot pan. If doing a large amount of peppers, do one pint at a time. Move pan to indirect heat if the pan is too hot.
Stir frequently and remove when you see blistering on the peppers. About 10 - 14 minutes. Remove and serve hot with dipping sauce. Dust with remaining kosher salt.
Dipping Sauce
In a small bowl combine all ingredients and stir.
Notes
Add wood chunks to lump charcoal for extra smoke flavor.Padron peppers are a great alternative using the exact same method.