Set a large nonstick skillet or wok on the stove and place a plate next to it for the cooked tofu.

Drain the tofu, pat it dry with paper towels or a clean kitchen towel, and set it on a towel-lined plate.

Lay another towel or more paper towels over the tofu and press gently for 5 minutes to remove extra water.

Put the tofu pieces in a medium bowl.

Sprinkle the cornstarch over the tofu in the bowl and toss gently until the pieces look lightly coated on all sides.

In a small bowl, stir together the soy sauce, chili crisp, sugar, and water until the sugar is mostly dissolved.

Heat the skillet over medium-high heat for about 1 minute. Add 2 tablespoons of the oil and swirl to coat the pan.

Add the tofu to the skillet in a single layer. Leave it alone for 3 to 4 minutes, until the bottoms look deep golden.

Turn the tofu pieces with tongs or a thin spatula and cook for 3 to 4 minutes more, until several sides are browned and the coating looks crisp.

Transfer the tofu from the skillet to the plate.

Add the remaining 1 tablespoon oil to the same skillet. Add the leeks and the white parts of the scallions.

Cook the leeks and scallion whites for 2 minutes, stirring often, until the leeks start to soften.