DIRECTIONS
Cut tuna into square pieces, about 1-inch size, set aside.
In a large bowl stir together first five ingredients through ginger until combined. Remove half of the marinade and set aside.
Toss tuna pieces into half of the marinade to coat. Marinade about 20 minutes covered in the fridge.
Evenly spread sesame seeds onto a plate or flat surface. Coat each piece of tuna with seeds. For best presentation, coat 4 adjacent sides, but leave the two opposite ends uncoated to keep meat exposed.
Heat olive oil in a large non-stick pan to medium-high heat. Add prepared tuna pieces and cook each sesame-coated side until lightly browned, about 15-20 seconds per side. Centers should be pink and rare.
Remove from pan and insert one toothpick into each. Serve with remaining sauce for dipping.