Prepare the Beans: If using dried scarlet runner beans, soak them overnight and then cook them in a pot of water for 1-1.5 hours until tender. Drain and set aside to cool.
Prepare the Vegetables: While the beans are cooling, dice the avocado, cherry tomatoes, and cucumber.
Make the Dressing: In a small bowl, whisk together olive oil, lemon juice, salt, and pepper.
Assemble the Salad: In a large bowl, combine the cooked and cooled scarlet runner beans, avocado, tomatoes, and cucumber. Drizzle the dressing over the top and gently toss everything together to combine.
Serve: Garnish with fresh parsley before serving.