To make the sauce, place all the ingredients in a high-Speed Blender and process until smooth, about one minute. Set aside.
Put the tapioca starch, salt and pepper in a large bowl and mix well. Cut each boneless chicken thigh in 2 or 3 pieces and add that meat to the bowl with the tapioca starch. Toss delicately with your fingers until all the pieces of chicken are evenly coated.
Melt the coconut oil in a large skillet set over high heat until it gets really hot. Add the pieces of chicken, leaving at least one or two inches between them so that air gets to circulate freely around them and they don’t start boiling as opposed to browning; work in batches if you have to.
Cook the chicken for 3 to 5 minutes per side, until it gets brown and crispy, and remove to a plate while you cook the remaining pieces.
Once all the pieces of chicken have been cooked, return them to the pan, lower the heat to medium and cook uncovered for an additional 5 to 6 minutes, until the chicken is cooked through and the juices that come out are no longer pink.
Add the sauce and mix until well coated; reduce the heat to medium-low and simmer for about 5 minutes, until the sauce is thickened and darker in color.
Serve immediately, garnished with green onions and orange zest and slices, if desired.