Cook the quinoa: Rinse quinoa under cold water until it runs clear. Heat 1 tablespoon olive oil in a saucepan over medium.
Add quinoa and toast for 1 minute, stirring. Pour in broth, add 1/2 teaspoon salt, bring to a boil, then reduce heat, cover, and simmer 15 minutes. Remove from heat and let stand covered 5 minutes.
Fluff with a fork.
Prep the veggies and sauce: While quinoa cooks, chop tomatoes, cucumber, bell pepper, cabbage, avocado, herbs, and green onions. Whisk together your chosen sauce in a small bowl. Adjust salt, acid, and heat to taste.
Brown the beef: Heat a large skillet over medium-high.
Add olive oil if using, then the beef. Break it up with a spatula and cook until mostly browned, about 4–6 minutes. Drain excess fat if needed.
Season the beef: Add onion and cook 2–3 minutes until softened.
Stir in garlic, cumin, smoked paprika, chili powder, oregano, salt, and pepper. Cook 1–2 minutes until fragrant. Squeeze in lime juice and taste for seasoning.
Assemble the bowls: Spoon quinoa into bowls.
Top with seasoned beef, then arrange tomatoes, cucumber, bell pepper, and cabbage around it. Add avocado last to prevent browning.
Add sauce and garnish: Drizzle with your sauce of choice. Finish with chopped cilantro or parsley and green onions.
Add a pinch of flaky salt if you like.
Serve: Enjoy warm. If prepping ahead, keep sauce and avocado separate until serving.