Cut the peppers, onions, and chicken into bite-size pieces. Set aside. If using frozen pineapple, thaw and put it in a blender or food processor and puree until smooth. Set aside.
In a medium saucepan over medium-high heat, combine 3/4 cup of the water, honey, vinegar, pureed pineapple and juice, and ketchup. Bring to a boil and then turn off the heat.
In a separate small bowl, combine the 1/4 cup tapioca starch and the remaining 1/4 cup cold water and stir to combine. Slowly pour into the sauce, stirring until the mixture thickens. Set aside.
While the sauce is coming to a boil, in a large skillet, saute the peppers over medium heat until they are just slightly tender, but still crunchy. Remove and set aside.
In a large bowl, combine cassava flour, potato starch, arrowroot starch, salt, pepper, oil, and egg. Add the water 1/2 cup at a time and stir to fully mix the batter until smooth. It should be thick enough to coat the chicken, not thin and runny. You may not need all the water.
Add the chicken pieces to the batter in the bowl and stir to coat all the pieces.
In the same skillet you used for the veggies, heat 1" of coconut oil over medium-high heat (about 360°F if you want to be precise). Time to get messy. Using your fingers, add the coated chicken pieces (one at a time) and cook in small batches, making sure not to overcrowd the skillet. Cook about 4-5 minutes, turning turning once, until golden brown. Remove chicken from oil and drain on paper towels.
Combine cooked peppers, onions, and chicken in a large serving bowl or platter, and pour the warm sweet and sour sauce over the top, stirring slightly to coat all pieces.
Serve over white rice (this is not paleo) or riced cauliflower.