Bring a small pot of water to a boil and cook the soba noodles for 4-5 minutes until tender, then drain and set aside.
In a small bowl, whisk together the coconut aminos, raw honey, grated fresh ginger, and minced garlic to create the glaze.
Pat the ahi tuna steak completely dry with paper towels and season both sides with sea salt and black pepper.
Spread the sesame seeds on a flat plate and press the tuna steak into the seeds to create an even crust on the top and bottom.
Heat the toasted sesame oil in a cast-iron skillet over medium-high heat until it begins to shimmer.
Place the tuna in the hot skillet and sear for 1-2 minutes per side for a rare to medium-rare center, ensuring the sesame seeds become golden and fragrant.
Remove the tuna from the pan and let it rest on a cutting board for 2 minutes before slicing into thin strips.
In the same skillet, add the baby bok choy and a splash of water, sautéing for 2-3 minutes until the leaves are wilted and the stems are tender-crisp.
Arrange the soba noodles and bok choy on a plate, top with the sliced tuna, and drizzle the sesame-ginger glaze over the entire dish.