Trim fat from steak. Slice steak diagonally across grain into thin strips. Combine steak and next 6 ingredients (steak through ground red pepper) in a zip-top heavy-duty plastic bag; seal bag, and shake well to coat.
Heat the tortillas according to package directions.
Heat 1 teaspoon oil in a large nonstick skillet over medium-high heat. Add steak, onion, and bell peppers; sauté 6 minutes or until steak is done. Remove from heat; stir in lime juice. Divide mixture evenly among warm tortillas, and roll up. Serve with sour cream. Garnish with green salsa and cilantro sprigs, if desired.
This was great! I've made other Cooking Light fajitas recipes that have required you to marinade the meat, and weren't as flavorful. I really liked how quick it was to add the spice blend to the sliced steak, then pop it in the pan and voila! six or seven minutes later, you're done. This was very tasty with very minimal effort. It was just the right amount of spicy for my husband and me, but if you like really spicy food, you could kick up the red pepper a notch.