In a bowl, mix the masa harina with 1 teaspoon of salt. Whisk in the warm water to form a soft dough. Cover with plastic wrap and let sit while you prep the filling.

Heat the olive oil in a medium skillet over medium heat. Add the scallions, minced garlic cloves, cumin, coriander and a pinch of salt and pepper. Cook until the scallions are softened and the garlic is fragrant, about 1 minute. Add the black beans and cook another minute. Remove from heat and squeeze in the juice from ½ lime. Stir in the cilantro, and season to taste with salt and pepper. Using a potato masher, smash the mixture until the beans are sticky, but with some whole beans remaining. Scrape the beans into a bowl and cool slightly. Stir in the grated cheddar. Form the filling into 4 balls.

Divide the masa dough into 4 balls. Working with 1 ball at a time, flatten it on a piece of wax paper into a 5-inch round. Place a black bean ball in the center and fold up the dough to cover the filling (the dough will be sticky). Flatten the ball gently into a 4-inch patty about 1-inch thick, patching up any holes or tears as necessary. Repeat with the remaining dough and filling. Do Ahead: The uncooked arepas can be transferred to a wax paper-lined baking sheet, covered with another piece of wax paper then tightly covered with plastic wrap and refrigerated for up to 24 hours. Bring to room temperature before frying.

Heat ¼ inch of grapeseed or vegetable oil in a large nonstick or cast iron skillet. Fry the arepas until golden and crisp on each side, about 3-5 minutes per side (I use a fish spatula to flip the arepas, with the help of a rubber spatula). Drain on paper towels and sprinkle with sea salt, then transfer to plates. Pile the Quick Red Cabbage Slaw on top of the arepas, and serve with pickled jalapeños and a dollop of sour cream. Do Ahead: The fried arepas (without toppings) can be transferred to a parchment-lined baking sheet and kept warm in a 200 degree oven for 30 minutes.