Drain the tofu, cut into two ¿steaks¿ and lay between paper towels. Press with a heavy skillet or cutting board for 20 minutes.
Drop the soba noodles in a pot of boiling water and boil for 4 minutes. Turn off the heat. Let sit for 1 minute, then drain and let rest covered with cold water. This keeps them from sticking together.
Whisk together the soy sauce, rice wine vinegar, sesame oil, brown sugar, garlic, ginger, mustard powder and white pepper in a large bowl. Drain the noodles and add to the dressing. Toss to coat. Add the red bell pepper and kale. Set aside.
Cube the tofu and arrange in a single layer on an oiled baking sheet. Spray with cooking spray and broil on low until browned, about 20 minutes.
Add the tofu to the noodles and toss all to mix. Keeps for 10 days, refrigerated.
Soba noodles are a Japanese buckwheat noodle. They can be found in most large grocery stores in the ethnic or Asian foods aisle.