Cut off wilted bits from the greens and discard and wash the remaining collards in cold ice water. Transfer to a strainer to drain, then coarsely chop the stems and leaves into 2- to 3-inch pieces.
In a large skillet, heat coconut oil over medium-high until rippling. Add the scallions and cook, stirring, until softened, about 1 minute. Add greens and cook, stirring, just until wilted, about 1 minute.
Add coconut milk and bring to a simmer. Simmer, uncovered, stirring frequently, until collards are cooked to your taste, about 7 minutes for bright and crisp greens or 10 minutes for darker, softer greens. Add the 1/2 tsp of turmeric (optional)
Season to taste with salt and pepper and serve immediately.