Mix cornstarch and water in a small bowl; set aside.
Brown ground pork in a small skillet over medium-high heat, about 5 minutes. Drain fat.
Heat the vegetable oil over medium-high heat in a large skillet or wok. Cook the garlic and ginger root in the oil until fragrant, about 1 minute. Stir in tofu and cook for 2 minutes. Season with the soy sauce, hot bean sauce, and sugar; stir to combine.
Stir in the cooked pork and green onion. Sprinkle with the cornstarch and water mixture; cook and stir until thickened, about 2 minutes. Stir the sesame oil into the thickened mabo tofu.