Cook the lentils: Rinse lentils and place them in a pot with 3 cups of water and one teaspoon of salt. Bring to a boil, then reduce heat to simmer and cook covered for 15-20 minutes, until lentils are tender. Drain well and set aside.

In a large heavy-bottomed pot or Dutch oven, heat the avocado oil over medium heat. Add the onion and cook for 15-20 minutes, stirring occasionally, until golden and deeply caramelized. Add the garlic, cumin seed, oregano, and chili flakes (if using), and toast for 1 minute. Season with 3 teaspoons salt and ¼ teaspoons pepper. Add the lentils and cauliflower rice into the pan and cook for 6-8 minutes, stirring frequently, until tender and combined. If needed, season with more salt and pepper.

Serve warm.