Whisk the vinegar, 1 tablespoon water, 1/2 tablespoon soy sauce and 1/2 teaspoon salt in a small bowl. Add the jalapeno; set aside.
Heat the vegetable oil in a medium nonstick skillet over medium-high heat. Add the tofu and cook until golden brown, 3 to 4 minutes per side; transfer to a cutting board. Add the mushrooms to the skillet and cook, stirring, until slightly wilted, about 1 minute. Add the remaining 1 1/2 tablespoons soy sauce, 1 tablespoon water and a few grinds of pepper to the skillet. Cook until the mushrooms soften, about 2 minutes. Quarter each piece of tofu and transfer to a bowl; add the mushrooms and 2 tablespoons of the vinegar mixture and toss. Set aside.
Meanwhile, bring a large pot of salted water to a boil. Add the noodles and cook as the label directs, adding the broccolini during the last 2 minutes of cooking. Drain and rinse under cold water; transfer to a large bowl. Add the sesame oil; toss to coat.
Divide the noodles and broccolini among bowls. Top with the tofu, mushrooms and sprouts and drizzle with the remaining jalapeno-vinegar mixture. Sprinkle with the scallions.