Combine the salsa ingredients in a bowl; toss to combine and set the salsa aside.
PREPARE THE FAJITAS:
In a separate bowl, combine the steak, chili powder, coriander and oregano; turn to coat the meat. Heat the oil in a large nonstick skillet over medium-high heat. Add the steak, onion, bell pepper, jalapeño, Worcestershire sauce and salt. Cook, stirring occasionally, 6 minutes. Remove from the heat.
Warm the tortillas in the oven or the microwave. Scoop some of the beef mixture in a strip down the center of each tortilla. Top with mango salsa and a tomato slice. Serve with a wedge of lime for squeezing. Add additional toppings such as sour cream, cheese and guacamole, as desired.
Notes
For those counting WW Points, you'll want to use lean flank steak and low carb flour tortillas.