Preheat your oven to 425°F / 220°C. Lightly brush both sides of the corn tortillas with 1 teaspoon (5 ml / 0.2 fl oz) of the olive oil.
Arrange them on an ungreased baking sheet and bake for about 6 minutes, turning once, until they are light brown and crisp.
While the tortillas are baking, heat the remaining 1 tablespoon (15 ml / 0.5 fl oz) of olive oil in a large skillet over medium-high heat.
Add the chopped onion, jalapeño, and minced garlic.
Cook, stirring occasionally, until the onion is tender.
Stir the rinsed black beans and chopped tomato into the skillet.
Cook until everything is heated through.
Remove the crisp tortillas from the oven.
Sprinkle them evenly with half of the shredded cheese. Spoon the warm bean mixture over the cheese, then top with the remaining cheese.
Return the tostadas to the oven and bake for about 4 more minutes, or until the cheese is perfectly melted and bubbly.
Sprinkle with fresh cilantro before serving.
Add a pinch of cumin and smoked paprika to the bean mixture while it cooks to deepen the flavor.
Don't be shy with toppings! A dollop of sour cream or cashew crema, sliced avocado, or a squeeze of fresh lime juice takes these tostadas to the next level.
When handling jalapeños, wear gloves to prevent the oils from irritating your skin. If you don't have gloves, wash your hands thoroughly with soap and warm water immediately after chopping.
