In a large mixing bowl, add the cooked black beans, arugula, sliced bell peppers, and sliced radishes.
In a separate small bowl, whisk together the olive oil, lemon juice, and sumac to create the dressing. Adjust seasoning with salt and cracked black pepper.
Pour the dressing over the salad mix and toss gently until all ingredients are well combined.
Garnish the salad with chopped cilantro and additional cracked black pepper if desired.
Serve immediately for the freshest taste, or let it chill for about 10 minutes to enhance flavors.
