Preheat oven to 400°F. Line a baking sheet with parchment paper and set aside.
In a small bowl, combine the ground flax and water. Give it a stir and let it sit for at least 5 minutes to “gel.”
Set a medium sauté pan over medium heat. Add the olive oil and swirl it around. Add the diced onions to the pan and stir. Sauté the onions until slightly soft and translucent, about 5 minutes. Add the garlic and oregano to the pan and sauté for another minute. Finally, add the nutritional yeast, chili, onion powder, salt, and pepper to the pan and stir for about 30 seconds. Pour in their lemon juice and scrape up any browned bits on the bottom of the pan. Take the sauté pan off the heat and set aside to cool.
In the bowl of a food processor fitted with the “S” blade, place the walnut halves and the oats. Pulse the walnuts and oats until you have a coarse meal. Transfer the meal to a large bowl.
Place the bowl of the food processor back on the motor base. Add the white beans to the food processor and pulse until they are ground up with a little bit of chunky bean bits still in the mix. Transfer the ground white beans to the large bowl with the ground walnuts and oats.
To the large bowl, add the flax gel mixture, sautéed onion and garlic mixture, tamari, lemon zest, parsley, dill, and big pinches of salt and pepper. Using a spatula or your hands, mix until thoroughly combined. Pinch off a bit of the mixture and give it a taste. Adjust the seasoning if necessary.
Measure out 2 tablespoons of the white bean and walnut mixture per meatball and roll it into a ball. Once you’ve rolled out all of the mixture, place the meatballs on the lined baking sheet. Lightly brush all of the meatballs with olive oil and then slide the baking sheet into the oven.
Bake the meatballs for 25 minutes, or until the tops have dried out a bit, the meatballs are firm, and the bottoms are browned. Serve the meatballs with pasta, on a platter with hummus and tahini sauce, or even in a grain bowl setup!