Wash and thoroughly dry mixed greens. Tear any large leaves into bite-sized pieces and place in a large serving bowl.
Rinse and drain black beans to remove excess sodium and starch.
Prepare corn kernels. If using frozen, ensure they're fully thawed and patted dry.
Dice the red bell pepper into small, uniform pieces about 1/4-inch in size.
Thinly slice the red onion. For a milder flavor, soak slices in cold water for 10 minutes, then drain and pat dry.
Add the black beans, corn kernels, diced bell pepper, and red onion to the bowl with the greens.
In a small bowl, whisk together lime juice and olive oil until emulsified. Season with salt and pepper to taste.
Drizzle the lime dressing over the salad ingredients.
Gently toss all ingredients until evenly coated with dressing, being careful not to bruise the greens.
Allow the salad to rest for 5 minutes to let the flavors meld together.
If using optional ingredients like avocado, cheese, or cilantro, gently fold them in just before serving.
Serve immediately as a refreshing main dish or flavorful side.
