Heat a large skillet or cast iron pan over medium-high heat. When the pan is hot, add the olive oil. Add the onions and peppers and cook until tender, about 5 minutes, stirring frequently. Add the mushrooms, water, and fajita seasoning. Stir until seasoning mixes in. Add the fresh lime juice, cilantro, and cook until the mushrooms are tender. Remove from heat and set aside.
To assemble the fajita bowls, fill bowls with fajita veggies, black beans, cilantro lime quinoa, tomatoes, lettuce, and avocado slices. Squeeze fresh lime juice over the bowls and serve.
Note-if you can't find fajita seasoning you can use taco seasoning. You can serve tortillas on the side, if desired. If you don't need the bowls to be vegan, feel free to add cheese, sour cream/Greek yogurt! You can also add chicken or steak to the mix! Go crazy and customize your bowls!