Start by preparing the carrot and daikon. Add the julienned carrots and daikon to a large bowl and toss in the sugar, rice vinegar, sesame oil, and salt. Set aside for 1 hour, stirring occasionally.
Meanwhile, heat a large non-stick pan over medium-high heat, and add the oil. Add the cornstarch to a shallow dish. Once the pan is heated, quickly coat the tofu slices with cornstarch, shaking off any excess. Carefully place into the oiled pan, and repeat with the remaining tofu and cornstarch.
Pan-fry the tofu pieces in oil until crisp and golden on both sides, about 4-5 minutes per side. Once the tofu is done pan-frying, remove them immediately from the pan onto a plate (otherwise they will absorb the remaining oil in the pan off the heat). Set aside.
With the pan over medium heat, add the sesame oil and garlic, and cook for 1 minute. Then add the water, sugar, fish sauce, and light soy sauce. Bring to a simmer. Increase the heat to medium-high, and stir in the tofu and lime zest. Toss the tofu with the sauce for 1-2 minutes, until the sauce reduces and thickens to coat the tofu.
Meanwhile, preheat the oven to 400°F/200°C. Place baguettes directly onto the oven rack and reheat for 6-8 minutes, until warm and crispy.
To assemble the sandwiches, combine the mayonnaise, Sriracha, and lime juice. Cut the baguettes in half crosswise, and open them up. Spread the sriracha mayonnaise on each side. Fill with the pickled carrots and daikon. Add some slices of tofu, sliced cucumber, sliced jalapeño, and cilantro. Serve!
Notes
You can make the carrot daikon salad and Sriracha mayo up to 3 days in advance. Store in airtight containers in the fridge. Everything else should be made fresh, and you should assemble the sandwich right before serving.