Cut tofu into bite-size pieces and lay them on paper towels to drain out excess water. Sprinkle salt over them.
Crisp up tofu in an air-fryer for 10-12 minutes at 400° F (204° C), bake it in the oven for 20 minutes at 400° F (204° C), or shallow-fry it in the same wok you'll use for the stir-fry.
Mix cornstarch, chili garlic sauce, sugar, Shaoxing wine, soy sauce, and ⅔ cup of water for the stir-fry sauce.
Set your wok to medium-high heat and add about a tablespoon of oil. Sauté ginger and garlic for about 30 seconds, then add scallions.
Add asparagus and cook for 2 minutes (less for thin asparagus). Toss them constantly, so they don't burn. Add the tofu.
Increase the heat and pour in the sauce immediately.
Toss them together and let the sauce thicken for about a minute. Add sesame oil and ground pepper to taste. Turn off the heat and serve.
Notes
Chili garlic sauce: A thick, chunky sauce made from red chilies and used in stir-fries and sauces. You can also use sambal oelek or Sriracha in place of it.
Shaoxing wine: An amber-colored Chinese rice wine that enhances the flavor of the dish. To substitute, use another Chinese cooking wine, dry sherry, or Japanese rice wine (sake).
Sesame oil: Choose the dark-colored variety made from toasted sesame seeds with a strong flavor and aroma. It is used for seasoning and is added toward the end of cooking.