Cook soba noodles according to package directions; drain and rinse with cold water. Build medium-hot fire in charcoal grill or heat gas grill to medium-high and grease grill grate.

Line cutting board with paper towel. Top with tofu and a couple more sheets of paper towel. Place another cutting board or other flat object on top and press gently to extract excess liquid from tofu. Turn tofu blocks on their sides and slice in half lengthwise.

Lightly brush tofu with 1/2 tsp sesame oil and season with salt and black pepper, if using. Grill tofu squares until golden and showing grill marks, about 4 minutes per side. Re-move from grill and, when cool enough to handle, slice into 1 inch cubes. Lightly brush bok choy with 1/2 tsp sesame oil. Grill until stalks are tender and leaves begin to darken and turn crispy.

In small bowl, whisk together lime juice, soy sauce or tamari, remaining 2 tsp sesame oil, fish sauce (if using), sriracha, sugar, shallot, and garlic.

Divide soba noodles among 4 serving plates and top with carrot, tofu, bok choy, cilantro, mint, and peanuts. Drizzle dressing over top.