Vegan Fajitas (on a Sheet Pan!)

Name: Vegan Fajitas (on a Sheet Pan!)
Prep time: 15 min
Cook time: 25 min
Total time: 40 min
Cuisine: Mexican, TexMex
Ingredients: 1 white onion; 2 bell peppers; 1 head cauliflower; 1 portobello mushroom; 2 tablespoons olive oil; 1 tablespoon chili powder; 1 teaspoon cumin; 1 teaspoon smoked paprika (or regular); 1 teaspoon garlic powder; 1 teaspoon onion powder; 1 teaspoon kosher salt; 2 ripe avocados; 1 lime; 1/2 teaspoon kosher salt; Fresh cilantro; 8 tortillas (flour or corn); 1 15-ounce can vegetarian refried beans or homemade refried beans