To remove kernels, place a small bowl inside a large bowl. Stand cob on its stem end on the small bowl and cut kernels off with a serrated knife or a sharp, thin-bladed knife. Once all the kernels are removed from the cob, using the back of a chef's knife, scrape the milk from the cob into the bowl.
Place a medium saucepan over medium heat and add the olive oil. Add the scallions, shallots, garlic, jalapeños, and red chile (if using) and cook, stirring occasionally until vegetables are soft but not browned, about 2-3 minutes.
Add the corn kernels and salt and cook, stirring occasionally with a wooden spoon until softened, about 5 minutes.
Add the coconut milk and let come to a simmer. Cook, stirring occasionally, until coconut milk starts to thicken, about 3-5 minutes.
Turn off the heat, taste and season with more salt if needed. Stir in cilantro and serve immediately.