• Step 1: In a large bowl, combine the masa harina and salt. Gradually add the warm water and knead the mixture until a smooth, pliable dough forms. Cover and let the dough rest for 30 minutes.
• Step 2: Divide the dough into 12 equal portions. Working with one portion at a time, use your hands to flatten the dough into a round, flat circle. Place a heaping tablespoon of refried beans and a sprinkle of shredded cheese in the center. Fold the dough over the filling and pinch the edges to seal, forming a half-moon shape.
• Step 3: Heat a large skillet or griddle over medium heat and lightly coat with vegetable oil. Cook the pupusas for 2-3 minutes per side, or until golden brown and heated through. Serve warm with curtido (Salvadoran cabbage slaw) and salsa roja (red sauce) on the side.