Whisk all the dressing ingredients together. Allow to sit in the fridge for at least 30 minutes.
For the sauce, combine coconut aminos, flour, pear juice, honey & sriracha in a small pot. Heat until simmering, about 5 minutes.
In another pan, heat oil. Lightly salt both sides of the ahi and sear for 1-2 min, flip and brush with the thickened sauce. Sear another 1-2 minutes for rare to medium rare.
Spread sesame seeds on a plate and coat both sides of the fish. Slice very thin. Combine lettuce and dressing. Place the seared tuna on top with radish, green onion, and mango.
This was restaurant quality! I was intimidated to try this but it actually was quite easy. Searing the tuna does not take long and the glaze with the sesame seeds makes it SO GOOD!