In a large skillet over medium heat, add sesame oil, then add frozen potstickers in a single layer. Sauté for 2-3 minutes until golden and crispy. Add water, cover, and steam for 5-6 minutes until heated. Transfer to a plate and set aside.

In a large pot of boiling salted water, cook the lo mein noodles or spaghetti according to package instructions, usually 5-7 minutes. Drain noodles, toss with sesame oil, and set aside.

In the same skillet, add another splash of sesame oil and minced garlic. Add shredded carrots and red cabbage, cooking for 2-3 minutes. Stir frequently, then add baby spinach or bok choy and cook until just wilted, about 1-2 minutes.

In a small bowl, whisk together soy sauce, oyster sauce, rice vinegar, sugar, and black pepper. Pour this mixture into the skillet, stirring well, then add the drained noodles, tossing everything together for 2 minutes.

Carefully add the potstickers back into the skillet and gently toss with the noodle and vegetable mixture. Cook for an additional 1-2 minutes, garnish with green onions and sesame seeds before serving.