Start by draining and rinsing your cooked gigante beans. This helps remove any residue and enhances their flavor.
In a large mixing bowl, combine the extra-virgin olive oil, fresh lemon juice, chopped parsley, chopped sun-dried tomatoes, chopped garlic, lemon zest, sea salt, red pepper flakes, and freshly ground black pepper. Whisk everything together until well blended.
Add the rinsed gigante beans to the bowl with the marinade. Gently fold the beans into the mixture, ensuring they are well-coated with the flavorful marinade.
Cover the bowl with plastic wrap or transfer the beans to an airtight storage container. Allow the beans to marinate in the refrigerator for at least 30 minutes. For deeper flavor, let them sit for a few hours or overnight.
Once marinated, give the beans a good stir. Taste and adjust seasoning with more salt, pepper, or olive oil if needed. Serve chilled or at room temperature.