Blanch the pig feet in a large pot of boiling water for 5 minutes to remove impurities, then drain and rinse thoroughly under cold water.
Heat the avocado oil in a heavy-bottomed pot or Dutch oven over medium-high heat and sear the pig feet until they are lightly browned on all sides.
Add the diced yellow onion, minced garlic, and sliced fresh ginger to the pot, sautéing for 3 to 4 minutes until the aromatics are soft and fragrant.
Stir in the cooked white beans, tamari, apple cider vinegar, sea salt, and black pepper, tossing to ensure the pig feet are well coated.
Pour in the water, ensuring the pig feet are mostly submerged, and bring the liquid to a gentle boil.
Reduce the heat to low, cover the pot with a tight-fitting lid, and simmer for 4 to 5 hours until the meat is tender and the broth is thickened.
Garnish the stew with freshly sliced green onions and serve warm in deep bowls.