1) Preheat oven to 400 degrees F. In a large skillet over medium-high heat, add a tablespoon of olive oil. Add corn and cook, stirring occasionally, until corn is blistered and browned in parts, 3-5 minutes. Transfer to large bowl and stir in tomatoes, scallions, 1 tablespoon cilantro, lime juice, and season with salt and pepper.
2) Wipe skillet clean and add another drizzle of olive oil. Add onions and cook until softened, 3-5 minutes. Then add jalapenos, garlic, and cumin and cook until fragrant, 30 seconds or so. Add rinsed black beans and broth and simmer until broth is mostly evaporated, about 5 minutes. Transfer to a medium bowl and mash until the mixture is mostly smooth, but some chunks are okay. Season with salt and pepper to taste.
3) Invert a baking sheet and line it with parchment paper. Brush a tortilla with olive oil. Smear a 1/4 of the bean mixture on the tortilla (leave some space around the edge). Top with 1/4 of the corn mixture, 1/4 of cheddar cheese, and 1/4 of queso fresco. Top with second tortilla, brushed with oil. Repeat layers. Make a second tart the same way.
4) Bake tortilla tarts for 20-22 minutes until they are bubbly in the center and crispy around the edges.
Cut tart into wedges and sprinkle with cilantro as a garnish. Serve immediately.