In a large bowl, combine the ground beef, pork rind breadcrumbs, finely chopped yellow onion, eggs, garlic, salt, and pepper.
Mix until everything is well combined. Scoop out about a spoonful of the mixture and roll it into meatballs. You should end up with about 16-20 meatballs, depending on the size you make them.
Heat the avocado oil in a large skillet over medium-high heat. Once hot, add the meatballs and cook for about 5 minutes per side, turning occasionally, until they're browned on all sides and cooked through.
While the meatballs are cooking, make the teriyaki pineapple sauce. In a bowl, whisk together the pineapple juice, coconut aminos, garlic, ginger powder, rice vinegar, red pepper flakes, and cornstarch until the cornstarch is fully dissolved.
Pour the sauce into the skillet with the meatballs and add the pineapple chunks. Cover with a lid and let everything simmer for 5-7 minutes, or until the sauce has thickened into a glossy glaze.
Give everything a gentle toss, spooning the sauce over the meatballs so they're well coated. Serve over cauliflower rice and top with sliced green onions.