Cook bacon in small saucepan over medium-high heat until the fat is render and the bacon is crisp, about 5 minutes. Drain off and discard all but 2 tbsp. fat. Add the black bean soup and cumin. Cook, stirring occasionally, until soup comes to a boil. Remove from heat; keep warm.
In medium bowl, stir together masarepa and salt. Add 2½ cups lukewarm water. Stir until combined; let sit 5 minutes. Using wet hands, knead dough until smooth. Divide dough into 8 portions; roll portions into balls.
Heat oil on large griddle, cast iron pan or non-stick skillet over medium-high heat. Add balls in batches, leaving at least 3” space between each one. Using palm offhand, flatten balls to ½” thickness. Cook, flipping once, until golden brown on both sides and heated through, about 7 minutes. Repeat with remaining dough.
Using knife, half arepas horizontally without detaching ends. Divide black bean filling and cheese among arepas.