In a large mixing bowl, combine the rinsed and drained black beans, chickpeas, diced tomatoes, and sweet corn. Gently stir these ingredients together until evenly mixed.

Fold in the chopped green chilies, finely diced red onion, and chopped green bell pepper. Include the optional jalapeño pepper if desired.

Sprinkle freshly chopped cilantro over the top and pour in the lime juice along with olive oil. Toss well to coat all ingredients.

Season with salt and pepper to taste and refrigerate covered for at least 30 minutes to allow flavors to meld.

Just before serving, add sliced avocados on top for a creamy finish.