Whisk together rice flour, coconut milk, 1 1/2 cups water, the turmeric, curry powder, 1/2 tsp. salt, the sugar, and green onions.
Heat 1 tbsp. oil in a large nonstick pan over medium heat. Add mushrooms and a pinch of salt and sauté until soft, about 10 minutes. Transfer to a bowl, discarding any juices.
Preheat oven to 200°. Wipe out pan and heat 1 tbsp. oil over medium-high heat. Add 1/4 of onions and 1/4 of pork. Cook, stirring, until fragrant, 2 minutes.
Whisk batter again and ladle about 3/4 cup into center of pan. Immediately tilt and rotate pan so batter quickly covers whole surface. Pile 1/4 of bean sprouts and 1/4 of mushrooms on 1 side of crêpe, close to center. Cover and reduce heat to medium. Cook until edges pull away from the pan, about 2 minutes.
Reduce heat to low, uncover, and cook crêpe until browned on bottom, 4 to 7 minutes.
Fold crêpe over and gently slide onto a plate. Cover loosely with foil and keep warm in oven. Make remaining crêpes the same way.
*Buy rice flour from an Asian market; the kind sold in supermarkets is too coarse.
Note: Nutritional analysis is per crêpe.