FOR THE DIPPING SAUCE:
4 1/2 tbsp. fresh lime juice
3 tbsp. Vietnamese fish sauce
3 tbsp. sugar
1 small, fresh, hot red chile (thai or serrano), stemmed
and sliced into thin rounds
FOR THE PORK:
1 small yellow onion, peeled and grated
2 tbsp. Vietnamese fish sauce
3/4 tsp. sugar
Freshly ground black pepper
1 1/2 lbs. boneless pork butt, trimmed of fat and thinly
sliced, then cut into 2" × 1" pieces
1/4 lb. dried rice vermicelli
1/2 head boston lettuce leaves, torn into pieces
1/2 bunch cilantro leaves, torn into pieces
1/2 bunch mint leaves, torn into pieces
Vietnamese herbs (optional), such as kinh giới and tiá tô,
torn into pieces