Combine chile powder, cumin, and 1/2 teaspoon salt in a small bowl. Sprinkle both sides of pork with chile mixture. Heat a large nonstick skillet coated with cooking spray over medium-high heat. Add pork; cook 4 minutes on each side or until done. Remove from pan; keep warm.
Heat oil in pan over medium-high heat. Add onion, peppers, and 1/2 teaspoon salt; sauté 4 minutes. Add garlic; sauté 1 minute. Remove from heat. Stir in juice.