Chop onions, garlic, and jalapeno if adding. *Don't worry about chopping the vegetables for the avocado sauce at this time, you can do that later.
In a large skillet with a lid, add about 2 tbsp of vegetable stock over medium heat.
Add in onion and saute for 2-3 minutes until it starts to get soft.
Add in garlic and cook for 1 minute.
Add in your seasonings: chili powder, red pepper flakes, cumin, smoked paprika, oregano, and salt, along with the tomato paste and jalapeno if adding. Stir together well. *It's okay if all the tomato paste isn't combined entirely.
Stir in rinsed, drained quinoa. Combine until all the tomato paste is incorporated. Toast the quinoa for 1-2 minutes, stirring constantly.
Add in remaining vegetable stock, beans and corn and bring to a boil.
Cover and lower the heat to simmer. Cook for 15 minutes.
If a lot of liquid remains, cook another 3-5 minutes.
Turn off heat, leaving covered for an additional 5 minutes.
Remove lid, stir together again and serve with your favorite taco shells and toppings.