Place a large non-stick pan over medium-high heat. Add 1 tsp. olive oil, ground beef and fajita seasoning to hot pan. Stir occasionally, breaking up meat, until no pink remains, 4-6 minutes.
If using steak strips, separate into a single layer, pat dry, and season with ¼ tsp. salt and a pinch of pepper. Follow same cooking instructions. If using chicken breasts, pat dry and season with a pinch of salt and pepper. Follow same instructions and stir occasionally until chicken reaches a minimum internal temperature of 165 degrees, 5-7 minutes. If using ground pork, follow same instructions, adding ¼ tsp. salt and a pinch of pepper, and stirring occasionally, breaking up with a spoon, until no pink remains, 5-7 minutes.
While beef cooks, prepare rice.