01 - Combine beef slices with 1 tbsp soy sauce and cornstarch in a medium bowl; toss to coat evenly and allow to marinate for 10 minutes.
02 - In a small bowl, whisk together remaining soy sauce, sriracha, hoisin sauce, brown sugar, rice vinegar, garlic, grated ginger, and sesame oil until fully blended.
03 - Heat a large skillet or wok over high heat with a splash of oil; sear beef in batches until browned and just cooked through, approximately 2 to 3 minutes per batch. Remove and set aside.
04 - Add additional oil to the skillet if necessary; stir-fry bell pepper, snap peas, and carrot for 2 to 3 minutes until tender-crisp.
05 - Return beef to skillet and pour in spicy sauce; toss all ingredients over high heat for 1 to 2 minutes until evenly coated and heated through.
06 - Spoon beef and vegetable mixture over steamed rice; garnish with sliced spring onions, toasted sesame seeds, and fresh cilantro if desired.