Melt the butter in a large pot, Dutch oven or wide skillet with a tight-fitting lid over medium heat. Add the pepper flakes, garlic, and salt, and cook until fragrant, about 30 seconds. Pour in the wine and raise the heat until it comes to a simmer (avoid a boil). Add the clams, cover, and adjust heat to maintain an active simmer. Cook until the majority of the clams open, about 6 to 9 minutes depending on the size of the clams. Give the pot a good shake about halfway through to move the clams around. Discard any that don’t open