Curry pastes vary widely in pungency and spice, so you may have to add more or less to this recipe according to the type you use. Both Asian mustard greens (which are pale and have a strong, spicy flavor) and leafy mustard greens will work in the recipe, or you can substitute Swiss chard or watercress.
1. Whisk together curry paste, sugar, garlic, and 2 Tbs. water in small bowl. Set aside.
2. Heat oil in wok or large skillet over medium-high heat. Add eggplant and onion, and cook 5 minutes, or until eggplant is browned. Stir in curry mixture, and cook 30 seconds, or until vegetables are coated.
3. Add mustard greens, and cook 1 to 2 minutes, or until leaves are wilted. Stir in coconut milk and 1 1/2 cups water, and season with salt, if desired. Cover, and bring to a simmer. Reduce heat to medium-low, and simmer 10 to 15 minutes, or until eggplant is tender. Serve with lime wedges.