Preheat oven to 425 degrees F (220 degrees C). Cover a baking sheet with aluminum foil, ensuring the foil goes up the sides of the sheet to catch all the juices.
Combine cauliflower, red bell pepper, red onion, olive oil, garlic, fajitas seasoning, cumin, and salt in a large bowl; stir until coated. Spread vegetable mixture onto the prepared baking sheet.
Roast in the preheated oven for 15 minutes; stir and continue roasting until tender and lightly browned, about 15 minutes more.
Top vegetable mixture with pinto beans, cotija cheese, cilantro, pepitas, green onions, and lime juice. Spoon into 4 serving bowls.