Rinse the romaine lettuce well and dry using a salad spinner or clean towels. Thinly slice the lettuce and place in a large mixing bowl. Then, add the thinly sliced scallions and chopped dill.
In a small bowl, whisk together the olive oil, lemon juice, sea salt, and black pepper until the mixture emulsifies.
Drizzle the dressing over the prepared greens. Gently toss the salad to coat the ingredients evenly. Finally, sprinkle the crumbled feta cheese on top and serve immediately.