Heat two large skillets over medium-high heat and spray with nonstick cooking spray. 

Drain and rinse black beans and corn, removing as much water as possible before adding to one skillet.

In the other skillet, add thawed cauliflower rice. If you're going straight from the freezer, pop it in the microwave for 3-4 minutes first. 

Leave both skillets untouched for 4-5 minutes.  

Add lime juice and salt to rice and stir. At this point, begin stirring the corn and beans, which should be slightly browning. (You can add any spices you'd like to the corn and beans like a bit of chili powder and paprika. Or if you like spice, a bit of cayenne pepper.)

Both skillets should be finished around the same time. (Maybe 8-10 minutes.) Don't sweat precision here. If you'd like your rice a bit crispier, keep it in the pan longer. Same for the corn and beans.

If you're reheating leftover carnitas, you can add them to one of the skillets during the last few minutes of cook time. 

You can get fancy with your plating or just add everything to one big bowl and top with pico and guac before diving in. I didn't include it in this recipe, but you could add a bit of fat-free shredded mozzarella for even more protein and flavor!