In a non-reactive bowl combine soy, honey
, and wasabi powder. Reserve 1/4 cup for dipping sauce. Roll each piece of tuna in this mixture to coat evenly. Marinate from 1 hour to overnight. Remove the tuna
from the marinade and discard the marinade
On a plate, lay the sesame seeds. Roll the tuna in the seeds to evenly coat.
Fire up the chimney and top with a well-oiled grate
for 15 to 30 seconds per side or to desired temperature. Remove to rack and rest for 3 minutes. Cover with foil or plastic wrap
to achieve carry over cooking. Slice thinly and serve with the dipping sauce.