Pictures: http://www.seriouseats.com/recipes/2013/01/fried-bee-hoon-singapore-noodles-recipe.html

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Soak all the rice vermicelli in hot water. If using dried shiitake mushrooms, soak those too.

1
Place sliced chilies in small bowl. Pour boiling water over to cover. Let sit 10 minutes, then drain. Add vinegar, soy sauce, sugar, and salt and stir to combine. Allow to cool.

2
For the stir-fry: Heat 3 tablespoons oil in wok over medium heat until shimmering. Add shallots, garlic, and mushrooms. Cook until mushrooms have softened and are beginning to brown, about 8 minutes.

3
Increase heat to medium high and stir in bok choy. Cook until beginning to wilt, about 1 minute. Add remaining 3 tablespoons oil. Add softened vermicelli, 2 tablespoons soy sauce, white pepper, and bean sprouts.

4
Cook, stirring, until seasonings are combined with noodles and noodles are beginning to brown on bottom of pan (add extra oil if beginning to stick), about 2 minutes. Season to taste with salt and/or soy sauce. Serve immediately with pickled chilies on the side.