Trim any excess fat from the boneless chicken thighs and cut them into bite-sized pieces, approximately four pieces per thigh. The skin is not required, as the chicken will be fried and coated in sauce.

Place the flour in a large mixing bowl. Dredge the chicken pieces evenly, ensuring they are fully coated. Cover with plastic wrap and refrigerate for at least one hour to allow the flour to bond with the chicken, resulting in a crispier texture when fried.

In a large bowl, combine shoyu, apple cider vinegar, brown sugar, Stevia, chili garlic sauce, honey, green onions, sesame oil, and sesame seeds (if using). Stir until the sugar has dissolved and the ingredients are well incorporated. Set aside.

Pour vegetable oil into a frying pan until it reaches approximately ½ inch in depth. Heat over high heat, then reduce to medium-high before adding the chicken to prevent burning.

Carefully place the floured chicken pieces into the hot oil, ensuring they do not overlap. Fry for approximately 5-6 minutes per side, flipping once a crust begins to form. Increase the heat to high during the final minute of cooking to achieve a golden-brown, crispy exterior.

Once the chicken is fully cooked and crisp, remove it from the oil and immediately dip each piece into the shoyu sauce mixture. Alternatively, place multiple pieces into the bowl and toss until evenly coated.

Transfer the coated chicken onto a plate lined with paper towels to absorb excess sauce while maintaining crispiness. Garnish with additional green onions or sesame seeds if desired. Serve immediately.