Preheat your oven to 400 degrees Fahrenheit. Line 2 large, rimmed sheet pans with foil and spray with non-stick cooking spray. Having all of the ingredients ready when you begin makes things quick and easy. You will start by preparing the cauliflower rice, then make the shrimp fajita mixture while the cauliflower is in the oven.
Place the riced cauliflower onto one of the prepared baking sheets. Add the garlic powder, salt, and pepper to a small bowl then pour in the avocado oil and lime juice, then stir to combine. Pour the mixture over the riced cauliflower and stir to coat, then spread the cauliflower rice into an even layer.
Place the prepared cauliflower rice onto the middle rack and bake at 400 degrees Fahrenheit for 10 minutes, then stir when it is time to add the shrimp to the oven. Make the shrimp fajita mixture while the cauliflower is in the oven.
While the cauliflower is in the oven, add the chili powder, garlic powder, cumin, salt, pepper, oregano, paprika, and chipotle chili powder to a small bowl, then add the avocado oil and stir to combine.
Add the shrimp, sliced bell peppers, and sliced onion to a large bowl, then pour the seasoned oil blend over the mixture and stir to combine. Pour the fajita mixture onto the 2nd prepared sheet pan and spread in a single layer. You can also mix everything on the sheet pan if you would prefer.
Stir the cauliflower rice, then return to the middle rack to continue baking and place the shrimp fajita mixture on the top rack. Bake everything for 10 minutes, or until the shrimp are pink and opaque, and the cauliflower is tender. To add a little char, turn the broiler on for about 2 – 3 minutes, and watch so that it does not burn.
Once everything has finished baking, carefully remove both sheet pans from the oven. Transfer the cauliflower rice to a serving dish then top with the shrimp fajita mixture. Squeeze fresh lime juice over the shrimp and sprinkle with freshly chopped cilantro. Serve with any additional toppings of your choice and enjoy!