Marinate the Steak:
In a bowl, whisk together lime juice, water, olive oil, minced garlic, Worcestershire sauce, soy sauce, salt, cumin, chili powder, red pepper flakes, and sugar.
Place the skirt steak in a resealable plastic bag or shallow dish and pour the marinade over the steak. Ensure the steak is well coated. Marinate in the refrigerator for at least 2 hours, preferably longer.

Prepare the Vegetables:
In a large skillet or on a griddle, heat 1 tablespoon of vegetable oil over medium-high heat. Add the sliced bell peppers and onion, sautéing until they are tender and slightly charred, about 6-8 minutes. Remove from the skillet and keep warm.

Cook the Steak:
Remove the steak from the marinade and pat dry with paper towels. Heat the remaining tablespoon of vegetable oil in the same skillet over high heat. Add the steak and sear each side for about 3-5 minutes for medium-rare, depending on thickness, or cook to your desired level of doneness.
Remove from heat and let the steak rest for a few minutes before slicing it against the grain into thin strips.

Assemble and Serve:
Serve the sliced steak with the sautéed bell peppers and onions on a sizzling platter if available. Provide warm flour tortillas and let guests make their own fajitas with the fillings.
Optional garnishes include sour cream, guacamole, salsa, cheese, and fresh cilantro.