In a measuring cup, whisk together the ingredients for the sauce.
Add shrimp to a gallon plastic bag. Add the tapoica flour, salt, and pepper. Shake vigorously to coat.
In a medium skillet over medium-high heat, add a little bit of vegetable oil. Once the oil is heated, add the shrimp to the skillet. Cook until slightly browned/crispy on one side. Remove from skillet and place on a plate.
Keeping the heat on, add the sauce to the skillet and bring to a low simmer to thicken. Once thickened, add shrimp back in and cook through. Toss to coat in sauce then remove from heat.
Top with sesame seeds and green onions, if desired. Serve over white or brown rice.