In a large bowl, whisk together soy sauce, brown sugar, garlic, ginger, sesame oil and Sriracha; set aside.
Heat olive oil in a large skillet over medium high heat. Add garlic, asparagus, carrots, bell pepper and zucchini. Cook, stirring occasionally, just until crisp-tender, about 3-4 minutes; season with salt and pepper, to taste. Set aside.
Cut beef into 8 serving-size pieces, pounded to 1/4-inch thickness, if needed.
Working one at a time, top each beef slice with vegetables, roll up and secure with a toothpick. Reserving 2 tablespoons, brush soy sauce mixture onto the roll ups and let sit for 10-15 minutes.
Preheat a gas or charcoal grill or place a grill pan over medium high heat.
Add roll ups to the grill, seam-side down, and cook until browned, about 2-3 minutes per side.
Serve immediately with remaining 2 tablespoons soy sauce mixture, garnished with cilantro and sesame seeds, if desired.