In a large pot of salted boiling water, blanch the okra until it’s bright green, about 30 seconds. Drain well and allow to cool to room temperature. Cut the okra into 1/2 inch pieces, and discard the stems.
Add the okra, beans, corn, onion, olive oil, sea salt, and pepper to a large mixing bowl, and toss gently until the olive oil is evenly distributed.
Chill for 30 minutes or more. Before serving, cut the avocado into 1/4-inch pieces and gently toss with the salad. Add more salt and pepper to taste if necessary.