Open the canned black beans with a can opener, then drain and rinse them thoroughly in a colander under cold running water until the water runs clear. This removes excess salt and bean juice, giving the beans a fresh, clean flavor.
Transfer the rinsed beans to a large mixing bowl. Add the finely chopped red onion and chopped cilantro, distributing them evenly throughout the beans.
Squeeze fresh lime juice directly over the bean mixture, then drizzle with olive oil if using. This adds brightness and a slight richness to the salad.
Sprinkle ground cumin and chili powder over the mixture, then season with salt and pepper to taste. Toss everything gently to coat the beans evenly with the spices and herbs.
Taste the salad and adjust seasoning if needed—add more lime juice for brightness or more salt for flavor balance.
Cover the bowl with plastic wrap and refrigerate for at least 30 minutes. Chilling allows the flavors to meld and intensify, making the salad even more refreshing.
Before serving, give the salad a gentle toss to redistribute the flavors. Taste again and add a final squeeze of lime or a pinch of salt if desired.
Serve the bright black bean salad chilled or at room temperature, garnished with extra cilantro if desired. Enjoy this simple, flavorful dish as a side or a light main.