Mix flour, salt, and water in bowl.
Knead dough for 8 minutes until smooth.
Rest dough covered for 30 minutes.
Heat oil in pot over medium heat.
Add pork pieces and brown all sides.
Add soy sauce, star anise, and ginger.
Pour water to cover meat halfway.
Simmer covered for 45 minutes until tender.
Divide dough into 6 equal portions.
Roll each portion into thin circles.
Cook flatbread in pan for 2 minutes.
Flip and cook other side golden.
Slice flatbread halfway through middle carefully.
Stuff with warm pork and juices.
Garnish with chopped green onions.