Prepare the Green Beans: Start by blanching the green beans. Bring a pot of salted water to a boil and add the green beans for about 3 minutes. Drain and immediately plunge them into an ice bath to stop cooking. This will help retain their bright color and crunch. Drain again and set aside.
Toast the Almonds: In a dry skillet over medium heat, add the slivered almonds. Toast them until they become golden and fragrant, stirring frequently to avoid burning. About 5-7 minutes should suffice. Remove from heat and set aside.
Stir-Fry the Vegetables: In a large non-stick skillet or wok, heat the vegetable oil over medium-high heat. Add the minced garlic and ginger, stirring quickly for about 30 seconds until fragrant.
Add the Vegetables: Toss in the sliced onion and bell pepper, stir-frying for about 2-3 minutes until they start to soften, but still retain some crunch.
Combine Everything: Add the blanched green beans to the skillet. Pour in the soy sauce, rice vinegar, hoisin sauce, and red pepper flakes. Stir well to coat the vegetables evenly. Cook for another 2-3 minutes until everything is heated through and nicely combined.
Final Touch: Season with salt and pepper to taste. Toss in the toasted almonds right before serving to keep them crunchy.
Serve and Garnish: Serve hot, optionally garnished with sesame seeds for extra flavor and presentation. Enjoy your vibrant green bean stir fry with your favorite protein or as a delicious standalone dish!