In a large mixing bowl, combine the black beans and corn.
Add the diced red bell pepper, chopped red onion, and cilantro to the bowl.
In a small bowl, whisk together the lime juice, olive oil, cumin, salt, and black pepper.
Pour the dressing over the bean mixture and stir until everything is evenly coated.
Lay out the romaine lettuce leaves on a serving platter.
Spoon the salad evenly into each lettuce leaf to form the cups.
Slice four olives in half lengthwise for the spider bodies. Cut the remaining olives into thin strips to use as legs.
Place one olive half on top of each filled cup and arrange four olive strips around it to form the legs.