Start by marinating the tofu. In a shallow dish, whisk together soy sauce, sesame oil, rice vinegar, brown sugar, garlic powder, and ground ginger. Add the tofu slabs, ensuring they are well-coated. Let marinate for at least 30 minutes, or up to 2 hours in the refrigerator for more flavor.
While the tofu is marinating, prepare the Sriracha aioli. In a small bowl, mix together mayonnaise, Sriracha sauce, lime juice, salt, and pepper. Adjust the seasoning to taste and set aside.
Heat vegetable oil in a large skillet over medium-high heat. Once hot, add the marinated tofu slabs and cook for about 4-5 minutes on each side, or until golden brown and crispy. Remove from heat.
To assemble the banh mi, spread a generous layer of Sriracha aioli on both sides of the baguette. Layer the crispy tofu, pickled carrots and daikon, cucumber slices, jalapeño (if using), and fresh cilantro.
Close the sandwich and slice it in half. Serve immediately and enjoy!