Put the oats and sunflower seeds in a food processor and pulse into a coarse meal. Transfer to a large bowl. Add the beets, flaxseeds, thyme, and fennel seeds and stir until well combined. Set aside.
Put the onion, mushrooms, garlic, and water in a medium skillet. Cover and cook over medium heat, stirring occasionally, until the vegetables are tender but not mushy, about 10 minutes. Let