Marinate the flank steak in soy sauce mixed with cornstarch for about 10 minutes.
Wash and slice all vegetables including bell peppers, broccoli, carrots, green onions, garlic, and ginger.
Heat vegetable oil in a large skillet or wok over medium-high heat. Add the marinated flank steak and cook for about 3-4 minutes until browned.
Add the peeled shrimp along with garlic, ginger, bell pepper, broccoli, and carrots. Stir-fry for an additional 4-5 minutes until shrimp are pink and vegetables are tender-crisp.
Season with salt, pepper, and toss in chopped green onions just before removing from heat. Serve hot garnished with sesame seeds.