For the dressing, whisk all ingredients together till combined. Allow to sit in the fridge for at least 30 minutes for the flavors to combine.Toast your sesame seeds by either broiling on high heat and watching VERY carefully for about 2 minutes or heating them in a skillet over medium heat.
For the ahi tuna, combine the coconut aminos, pear juice, honey, flour, sriracha in a small pot. Heat over medium high heat until simmering. Allow to simmer till thickened - about 5 minutes.
In another non-stick or cast iron pan, heat oil over medium-high heat. Lightly salt both sides of the ahi and add to the pan. Sear for 2 minutes on the first side, flip and brush with the thickened sauce. Sear another 2-3 minutes. I did 3 and mine was more medium-rare than rare. Remove from the pan and brush with the remaining sauce.
Spread your sesame seeds on a plate and lay your tuna on them, coating both sides of the fish. Slice and serve.