Whisk together the soy sauce, water, rice vinegar, sugar, garlic, ginger, and red pepper flakes. Set aside.
In a small bowl stir corn starch into cold water til dissolved. Set aside.
Drizzle a large skillet with sesame oil. Add beef strips and saute over medium-high heat for 2-3 minutes.
Add snow peas, and broccoli and continue to saute 2-3 minutes longer until veggies are tender and beef is browned.
Add soy sauce mixture. Bring to a boil.
Stir in corn starch slurry, stir til sauce thickens.
Reduce heat to low, stir in green onions and cooked ramen noodles.
Garnish with sesame seeds if desired and serve.
