1. Place sliced peppers, onion, and mushrooms in a large bowl and set aside.
2. Make marinade/sauce: In a small bowl, combine lime juice, Worcestershire sauce, minced garlic, cumin, smoked paprika, chili powder, salt, and whisk to combine.
4. Working in two batches, warm 2 tablespoons of olive oil in a large skillet over medium-high heat. Add half of your vegetables and cook for around 5 minutes, until they become slightly tender (we don't want limp veggies here, we want a tender-crisp texture).
5. Remove veggies from skillet using tongs or a slotted spoon (try to leave liquid in the pan to avoid soggy fajitas). Repeat process with remaining olive oil and vegetables.
6. While vegetabless are cooking, warm and char the tortillas by placing them over a gas burner (or grill) for a few seconds per side, using tongs to flip them. Alternatively, wrap tortillas in foil and warm in a preheated 350 degree F. oven for 10 minutes.