1. Trim flank steak of any fat, and slice into 1/4 inch thick strips, making sure to cut against the grain of the meat. The strips should be about 4-5 inches long. Thread onto bamboo skewers and place in a resealable bag.
2. Mix together orange juice and zest, lime juice and zest, hoisin, honey, Sriracha and garlic, and pour over flank steak skewers reserving 1/4 cup of the marinade to drizzle over the cooked steak. Refrigerate and let marinate at least 30 minutes.
3. Preheat large skillet or grill to medium high heat. Remove the skewers from the marinade and blot on a paper towel to release excess marinade. Sear, for 2-3 minutes per side until brown and caramelized.
4. To serve, place cooked skewers on a serving platter, drizzle with reserved marinade, chopped peanuts, scallions, cilantro and additional Sriracha, if desired.