Soak skewers for 30 minutes. Puree cilantro, garlic, soy sauce, orange zest, sriracha, fish sauce and sugar in a food processor. Transfer marinade to a resealable plastic bag; add beef. Seal bag, toss and set aside up to 30 minutes.
Combine dipping sauce ingredients in a bowl.
Thread 4 pieces of pepper and 2 beef strips on each skewer, alternating beef and peppers. Coat grill rack with cooking spray; heat grill to high; cook until meat is no longer pink, about 3 minutes.