For the tofu, heat olive oil in a large pan over medium-high heat. After 90 seconds, when the oil is hot, add the crumbled tofu. Cook for 6-7 minutes, stirring occasionally, until crispy and lightly browned all around.
Add the sriracha and hoisin sauce, stirring to coat the tofu evenly. Cook for 1-2 more minutes, until the sauce caramelizes into the tofu, then transfer to a plate and set aside.
Meanwhile, soak the dried rice vermicelli in warm water for 10 minutes, or until softened but still slightly firm. Drain and set aside.
In a small bowl, whisk together the tamari, tamarind concentrate, vegetarian oyster sauce, rice vinegar, and sugar until the sugar dissolves. Set aside.
To stir-fry, heat olive oil in a Dutch oven or wok over medium-high heat. After 90 seconds, when the oil is hot, add the shallots, scallions, garlic and bird’s eye chilies, stir-frying for 4 minutes until fragrant.
Increase to high heat and add the drained noodles. Pour in the prepared stir-fry sauce and toss everything together, stirring continuously, for 2–3 minutes until the noodles are evenly coated and heated through.
Add the cooked tofu and bean sprouts, stirring for 1 more minute until combined. Remove from heat.
Serve immediately, topped with cooked vegan egg if using, along with additional raw bean sprouts, cilantro leaves, minced scallions, and sliced bird’s eye chilies if desired.