Toss cucumbers and a few pinches of salt in a colander. Let sit until salt begins to draw out water from cucumbers, about 5 minutes. Transfer cucumbers to a small bowl. Add ginger and 1 Tbsp. vinegar and toss to combine. Chill until ready to use. Whisk chili, tamari soy sauce, honey, and 3 Tbsp. vinegar in a medium bowl. Cut tofu into 9 square pieces by cutting the block into thirds, then cutting each third crosswise into 3 pieces. Pat dry. Heat oil in a medium nonstick skillet over medium-high. Cook tofu, undisturbed, until very crisp and dark brown underneath, 4–5 minutes. Transfer tofu to a plate; wipe out skillet. Heat skillet over medium-high. Return tofu to skillet and add soy sauce mixture, turning tofu occasionally and reducing heat to medium if needed, until glaze is almost thick enough to coat a spoon, about 4 minutes. Meanwhile, cook soba noodles according to package directions; drain. Transfer tofu to a plate, leaving sauce in pan. Pour sauce into reserved medium bowl. Whisk in tahini and remaining 1 Tbsp. vinegar. Add noodles and toss until coated with sauce. Divide noodles among bowls. Top with tofu, pickled cucumbers, and spring onions.