Place the cashews, water, mayonnaise, lime juice, hot sauce, and one teaspoon of salt into a high-powered blender or food processor. Blend until smooth, stopping to scrape down the sides of the pitcher or bowl as needed. Set this aside.
Melt the vegan butter in a medium skillet over medium heat. Once the butter has completely melted, add the onion. Sweat the onion while stirring occasionally until it begins to soften, about 5 minutes.
Add the corn to the skillet and raise the heat to medium-high. Cook the corn by letting it sit in the hot skillet for about a minute at a time, then stirring. Do this for about 5 minutes, until the corn is tender-crisp and browned in spots.
Stir in the garlic, jalapeño, chili powder, cumin, and smoked paprika. Stir to coat the corn with the spices, then cook the mixture for about a minute, until it becomes very fragrant.
Lower the heat to medium, then pour the cashew mixture over the corn. Stir well to distribute the ingredients.
Cook the mixture for a minute or two, stirring constantly, until it is heated throughout and just starting to bubble. You can thin it with some water if the sauce gets too thick.
Remove the skillet from heat. Season the dip with additional salt to taste, along with some black pepper. Stir in the cilantro. Feel free to adjust any other seasonings to your liking at this point.
Transfer the dip to a serving dish, then garnish with additional fresh cilantro and jalapeño slices, if desired. Serve warm, with corn chips or tortilla chips.