In a medium-size mixing bowl, combine worcestershire, soy sauce, rice vinegar, lime juice, garlic, ginger, red pepper flakes, and cilantro.
Add the sirloin cubes into the bowl and toss to coat. Cover and refrigerate at least 4 hours.
Soak wooden skewers in water for at least 30 minutes before use.
Preheat a gas grill to high heat. Remove the steak from the fridge and thread onto skewers, leaving a little space between each cube to allow for even cooking.
Cook on the grill until desired doneness is achieved. For medium rare this should only be 1 minute per side for a total of 4 minutes.