Prep the vegetables. Rinse and snap off the tough end of the green beans. Set aside. Rinse the nameko mushrooms and set aside. Give the peppers a quick rinse.
Heat a skillet over medium-high heat. When the skillet is hot, add 2 tablespoons of olive oil. Reduce the heat to medium-low. Grill the peppers until they blister. Roll the peppers around so that the sides of the pepper are grilled. It took me about 8 to 10 minutes. Season the peppers with a pinch of salt, and turn off the heat. Serve the peppers on a plate once they're done.
Heat another skillet over medium-high heat. When the skillet is hot, add the remaining 2 tablespoons of olive oil. Add the onions, chili pepper, and ginger to the oil. Let them sizzle for a minute and then add the garlic. When the onions start to turn translucent, add the green beans.
Turn down the heat a little, and spread the beans out to an even layer. Let it cook for a few minutes and then add the mushrooms and scallions and stir. The green beans will be done when they turn into a nice emerald green color (about a few more minutes). Add the Thai basil when the green beans are almost done. Season with the remaining salt and oyster sauce, and turn off the heat.
Serve the green bean stir-fry and the peppers with a side of rice.
Refrigerate any leftovers in an airtight container.