In a very large, heavy pot with a tight-fitting lid, heat 1/4 cup of the oil over high heat until it's very hot, just to the point of smoking. Add a handful of collards, water droplets still clinging to them, to the pot (be careful, this will sputter). Stir vigorously with long tongs or a wooden spoon until the greens are wilted. Continue adding handfuls of wet collards, stirring until they wilt before adding more. Add the salt and the remaining 1/4 cup oil and stir well. Reduce the heat to low, cover the pot, and let the greens braise for 15 minutes.

Taste the greens; if they're not tender enough for your taste, continue the cooking, covered and over low heat, until they're done to your liking. If you're making them ahead, let the collards cool and then refrigerate. Reheat them by bringing them to a boil, reducing the heat to low, and simmering for about 5 minutes.