Combine 1 tablespoon of the balsamic vinegar with the sugar in a small bowl and mix well; set aside. Turn on the exhaust fan and heat a heavy 12-inch skillet or large wok over high heat for 2 minutes. When the pan is hot, pour in the oil and, a few seconds later, add the green beans, garlic, and shallot. Season the beans well with salt and pepper and cook, stirring often, until they brown and shrivel slightly, 3 to 4 minutes. Reduce the heat to medium-low, carefully add the water (it will steam), and a few seconds later add the vinegar mixture. Stir the beans and cover the pan with the lid ajar. Cook until the beans are tender but still have a slight crunch, about 4 minutes. (If the water evaporates before the beans are done, add more, 1 tablespoon at a time.) Stir in the remaining 2 teaspoons balsamic vinegar. Add the butter and almonds and swirl the pan just until the butter is melted. Season to taste with salt and pepper and serve immediately.