Start by rinsing the dry quinoa under cold water in a fine mesh strainer to remove any bitterness.
In your large pot or Dutch oven, combine the rinsed quinoa, 2 cups of water, and 3/4 cup of your chosen salsa. Stir to mix everything together.
Add the diced green pepper and sliced zucchini to the pot. Mix well to combine all the ingredients.
Bring the mixture to a boil over medium-high heat. Once boiling, reduce the heat to low, cover, and simmer for about 15 minutes.
After 15 minutes, remove the lid and stir in the cooked black beans. Cover again and let it cook for an additional 5 minutes.
Once the quinoa is done cooking, remove the pot from the heat. Stir in the chopped cilantro, adjusting the seasoning if needed.
Scoop the One-Pot Tex Mex Quinoa into bowls and serve warm. Top with additional salsa, avocado, or cheese if desired!