MAKE SAUCE:

STIR TOGETHER BROTH, BEAN PASTE, SOY SAUCE, AND KOSHER SALT. SET ASIDE.

POACH TOFU:

SLIDE TOFU INTO A SAUCEPAN OF SIMMERING WATER AND KEEP AT A BARE SIMMER WHILE STIR-FRYING REST OF DISH.

STIR-FRY PORK:

HEAT A WOK OR LARGE HEAVY SKILLET OVER HIGH HEAT UNTIL HOT AND ADD 1 1/2 TABLESPOONS CORN OIL, SWIRLING TO COAT. ADD PORK AND STIR-FRY, BREAKING UP LUMPS AND ADDING REMAINING 1/2 TABLESPOON CORN OIL IF MEAT STICKS, UNTIL NO LONGER PINK. ADD GARLIC AND GINGER AND STIR-FRY OVER MODERATE HEAT UNTIL VERY FRAGRANT, ABOUT 2 MINUTES.

FINISH STIR-FRY:

STIR RESERVED SAUCE, THEN ADD TO PORK AND BRING TO A SIMMER. DRAIN TOFU IN A LARGE SIEVE AND SLIDE INTO SAUCE, STIRRING GENTLY.

STIR CORNSTARCH MIXTURE AND ADD TO STIR-FRY. BRING TO A BOIL, STIRRING GENTLY, AND COOK UNTIL THICKENED AND GLOSSY, ABOUT 15 SECONDS.

TURN OFF HEAT AND SPRINKLE WITH SESAME OIL, SICHUAN-PEPPERCORN POWDER TO TASTE, AND 2 TABLESPOONS SCALLION. STIR ONCE OR TWICE, THEN SERVE SPRINKLED WITH REMAINING TABLESPOON SCALLION