Prepare the vegetables: Dice the tomato, red bell pepper, and onion into small pieces. Finely chop the cilantro and jalapeño. If using frozen corn, be sure to thaw it before use.
Mix the ingredients: In a large bowl, combine the black beans, corn, diced tomato, red bell pepper, red onion, cilantro, and jalapeño (if using).
Season the salsa: Add lime juice, olive oil, salt, black pepper, cumin, and chili powder. Stir everything together until well combined
Chill (optional): Cover the bowl with plastic wrap and refrigerate the salsa for at least 30 minutes to let the flavors meld. However, you can serve it immediately if you're short on time.
Taste and adjust: Before serving, taste the salsa and adjust the seasoning if necessary. Add more lime juice or salt to taste.