Heat the avocado oil (for the sauce) in a large pan on medium heat. Add in the ginger and pepper and cook until the pepper just begins to soften, about 2 minutes.
Whisk together all the remaining sauce ingredients except the starch and salt. Pour into the pan and turn the heat to medium/high. Bring a boil.
Once boiling whisk the 1 tsp of starch with 2 tsp of the hot sauce in a separate small bowl until smooth. While constantly stirring, pour the tapioca mixture back into the pan and stir until combined. Boil, stirring constantly, until the sauce thickens, reduces and is very shiny, about 2-3 minutes. Transfer to a large bowl and cover to keep warm. Season with salt to taste.
Place the tapioca starch and a pinch of salt in a large zip-loc bag. Add in the chicken and toss until coated.
Heat 1 Tbsp of the oil up in a large frying pan over medium high heat. add in half the chicken and cook until golden brown, about 2-3 minutes. Flip and repeat on the other side. Once cooked, transfer to a paper towel lined plate and blot off any excess oil. Repeat with remaining oil and chicken.
Transfer chicken to the bowl with the sauce and add in the pineapple. Stir until well coated.
Serve over cauliflower rice with green onion and sesame seeds.