Cook the quinoa: Add rinsed quinoa, broth, and salt to a pot. Bring to a boil, reduce to low, cover, and simmer 15 minutes.
Remove from heat and let sit, covered, 5 minutes. Fluff with a fork.
Sauté aromatics: Warm olive oil in a skillet over medium heat. Add onion and cook 3–4 minutes until softened.
Stir in garlic for 30 seconds.
Season the beans: Add black beans, tomato paste, taco seasoning, and water. Stir and simmer 3–4 minutes until saucy. Taste and adjust salt, pepper, or seasoning.
Mix the drizzle: In a small bowl, whisk yogurt, lime juice, honey, salt, and chili powder until smooth.
Thin with a splash of water if needed.
Prep toppings: Halve tomatoes, dice avocado, slice red onion, and chop cilantro. Warm corn briefly in the skillet or microwave.
Assemble: Divide quinoa into bowls. Top with taco beans, tomatoes, corn, avocado, onion, lettuce, and cheese if using.
Spoon over the lime yogurt drizzle and finish with cilantro and a squeeze of lime.