Press and prep the tofu: Wrap tofu in a clean towel and press for 10–15 minutes. Cut into 3/4-inch cubes. Toss with 1 teaspoon soy sauce and the cornstarch until lightly coated.
Mix the sauce: In a small bowl, combine soy sauce, rice vinegar, maple syrup, sesame oil, minced garlic, and chili-garlic sauce if using.
Set aside.
Cook the noodles: Boil udon per package directions until just tender. Drain and rinse briefly under hot water to prevent sticking. Toss with a splash of sesame oil.
Crisp the tofu: Heat 1–2 tablespoons neutral oil in a large nonstick skillet over medium-high.
Add tofu in a single layer. Cook 3–4 minutes per side until golden and crispy. Transfer to a plate.
Sauté the veggies: In the same skillet, add a little more oil if needed.
Add carrot and the white parts of the green onions. Stir-fry 2 minutes. Add kale and cook another 2–3 minutes until wilted but still bright.
Bring it together: Return tofu to the skillet.
Pour in the garlic soy sauce and toss until everything is glossy and coated, 30–60 seconds.
Add noodles: Add udon and toss gently over medium heat for 1–2 minutes so the noodles soak up the sauce. If it looks dry, splash in a tablespoon of water.
Finish and serve: Remove from heat. Top with green onion greens and sesame seeds.
Taste and adjust salt, sweetness, or heat. Serve with lime wedges if you like.