Drain the bean thoroughly and then rinse them under running water. Once drained and rinsed, allow the beans to fully air dry before proceeding to the next step.
Meanwhile, add anchovies, pitted olives, capers, parsley, olive oil, and vinegar to a blender. Add a pinch of salt and ground black pepper. Blend the ingredients on high speed until a smooth, homogenous mixture forms.
Dice the tomatoes into small, even cubes.
Once the beans have fully drained, place them in a large mixing bowl. Pour the blended sauce over the beans and use a rubber spatula to gently fold and coat the beans until fully incorporated.
Add the diced tomato to the bean mixture and carefully incorporate without over-mixing the ingredients.
The borlotti bean salad is now ready for immediate serving. Alternatively, it can be stored in an airtight container in the refrigerator until needed.