Heat the cooking oil in a wok. Saute the onion, garlic, ginger and chilies until fragrant, about 30 seconds.
Add the yard-long beans. Sprinkle with salt and pepper. Stir. Pour in about three tablespoonfuls of water. Cover the pan. Lower the heat to medium and cook for five minutes.
Add the squash and eggplant cubes. Sprinkle with more salt and pepper.
Pour in the coconut milk. Stir to combine. Bring to a simmer. Cover the pan once again and cook over medium-low heat until all the vegetables are done and the sauce has thickened and reduced.
A tip. To prevent the squash and eggplant cubes from losing their shape, avoid stirring after coconut milk starts to simmer. This isn’t a stir fried dish and frequent stirring will do more harm than good.