To make the dressing, whisk together soy sauce, rice vinegar, honey, sesame oil, and chili sauce or sriracha. Set aside.
Preheat oven to 400°F. Cut tofu into 1-inch cubes and arrange them in a single layer on a baking sheet lined with parchment paper. Coat tofu with cooking spray or vegetable oil and season with salt and pepper. Bake until golden brown, flipping halfway through, about 40 minutes total.
Meanwhile, cook soba noodles according to package instructions. Drain and rinse noodles under cold water, and set aside.
When ready to serve, pour the dressing over the noodles and vegetables, and toss well to coat. Top with tofu and garnish with green onions and sesame seeds.