Cook the quinoa in vegetable broth according to package instructions. Set aside.
Heat sesame oil in a large skillet over medium heat. Add tofu and cook until crispy on all sides. Remove and set aside.
In the same skillet, add garlic and ginger, cooking until fragrant.
Add mixed vegetables and cook until tender-crisp, about 5 minutes.
In a small bowl, mix soy sauce, hoisin sauce, sesame oil, and cornstarch slurry. Pour over vegetables.
Return tofu to the skillet, stirring to coat. Cook for 2-3 minutes until sauce thickens.
Serve the stir-fry over quinoa and garnish with sesame seeds and green onions.