Set up your colander and rinse the canned black beans thoroughly under cold running water until the water runs clear. Let them drain completely, then transfer to a large mixing bowl. You should have firm, glossy beans that are ready to soak up flavors.
Finely chop the red onion and fresh cilantro using a sharp chef’s knife. Add both to the bowl with the beans. The vibrant green and purple hues will brighten up the dish visually and aromatically.
In a small jar with a lid, combine the olive oil, lemon juice, a pinch of salt, and chili flakes if you like some heat. Shake the jar vigorously for about 20 seconds until the dressing appears slightly emulsified and fragrant.
Pour the dressing over the beans, herbs, and onion in the bowl. Gently fold everything together with a spatula or wooden spoon, making sure the beans are coated evenly and the herbs are distributed throughout.
Taste the salad and add more salt or lemon juice if needed to enhance the brightness and balance the flavors. Keep in mind that the flavors will meld better after a brief rest.
Let the salad sit at room temperature or in the fridge for about 10 minutes to allow the flavors to develop. Give it a gentle toss before serving to refresh the herbs and ensure the dressing is well distributed.
Serve the black bean salad in bowls, garnished with extra cilantro if desired. It can be enjoyed immediately or chilled further for a more refreshing experience. Its vibrant appearance and fresh flavors make it perfect for a light lunch or side dish.