In a large skillet or wok, heat the vegetable oil over medium-high heat. Add the frozen potstickers and cook for about 5-7 minutes, turning occasionally, until they are golden brown and heated through.
Add the sliced bell peppers, broccoli florets, and snap peas to the skillet. Stir-fry for another 3-4 minutes until the vegetables are tender-crisp.
Stir in the minced garlic and ginger, cooking for an additional 1 minute until fragrant.
Pour in the soy sauce and sesame oil, tossing everything together to coat evenly. Cook for another 1-2 minutes until heated through.
Remove from heat and garnish with sliced green onions and sesame seeds if desired. Serve hot.