How to Make It
Bring a large saucepan of water to a boil. Add the green beans and 1 tablespoon of salt and cook until the beans are tender, about 5 minutes. Using a slotted spoon, transfer the beans to a colander and rinse under cold water. Drain, pat dry and transfer to a large serving bowl.
Return the water to a boil. Add the potatoes and cook until tender, about 7 minutes. Drain and shake dry, then add to the beans in the bowl. Add 1/4 cup of the olive oil and gently toss to coat. Scatter the tomatoes, olives and onion slices over the top.
In a small bowl, combine the remaining 2 tablespoons of olive oil with the lemon juice and oregano and season with salt and pepper. Drizzle the dressing over the salad. Alternate the halved eggs and the anchovies around the edge and serve.
Salted anchovies taste best in this salad; they are easily cleaned by pulling apart the 2 fillets (discarding the backbone) and rinsing them quickly under running water. If you can't find salted anchovies, look for large, plump fillets packed in olive oil in a jar.