Dice pork belly to 1/2 inch cubes with skin on. Dice all vegetables.
Mince ginger, green onion, and garlic
Add 1 tablespoon oil, cook pork belly in it, until pork belly is crispy (about 5 minutes)
Drain the oil from the pork belly into the sink.
Add minced ginger, green onion, garlic and stir fry with pork belly till aromatic.
Add diced cabbage, onion, mushroom and stir fry 2 minutes.
Make an empty spot at center of pot and ddd black bean sauce to center of pot, stir fry for 30 seconds till aromatic.
Mix black bean sauce in with rest. Add 1.5 cup stock stock. Cover and cook for 10 minutes.
Meanwhile cook the noodles in a separate pot, by bringing to boil 2 portions of noodles (x oz) with enough water to cover the noodles.
Remove about 5 tablespoons of starchy noodle water, mix in 1 teaspoon cornstarch till dissolved. Add 1 tablespoon sugar. Mix well. Add this slurry to the sauce to thicken it.
Add 1 tablespoon sesame oil to sauce to make it shiny (key step!). Turn off stove, sauce is done!
Cut 1/4 of a cucumber into matchsticks by slicing in diagonal discs and then slicing discs vertically along long end.
Rinse noodles under cold water to make chewier. Add 1 portion noodles to serving plate, add sauce, and garnish with cucumber.
(optional: fry two eggs sunny side up and garnish on top of each bowl of noodle)