Pat tofu dry, toss cubes with cornstarch until evenly coated.
Heat vegetable oil in wok over medium-high heat.
Fry tofu until golden and crispy, about 6–8 minutes. Remove and set aside.
In same wok, sauté garlic and ginger until fragrant.
Add bell pepper, broccoli, carrot, and snap peas. Stir-fry 4 minutes until tender-crisp.
Whisk soy sauce, hoisin, vinegar, maple syrup, sesame oil, water, and chili flakes in small bowl.
Return tofu to wok, pour sauce over mixture.
Stir-fry 3 minutes, ensuring tofu and veggies are coated.
Garnish with scallions and sesame seeds before serving hot.