In a dish, mix together the olive oil, Worcestershire sauce, lime juice, garlic, cumin, chili powder, red pepper flakes, salt, pepper, and sugar until combined.
Pour half of the marinade into a zip lock bag; add the flank steak and turn it over to coat. In second zip lock bag, place all the veggies, turning to coat. Place in the fridge for at least 2 hours.
Place meat on heated grill with vegetables to the side in a wire grated pan. Turn meat after 5 minutes and cook until done, about another 5-6 minutes. Once beef is cooked, place on cool side of grill or remove from heat. Continue to toss vegetables and adjust heat until they are tender; usually about 10-15 minutes total. Take meat and vegetables off grill and let rest for 4-5 minutes.
Slice the meat right before serving and serve with all the fixins.