Bring a small pot of water to a boil; cook the pasta until al dente and boil the whole egg for 7 minutes for a jammy yolk.
Drain the pasta and place the egg in an ice bath before peeling and halving.
Heat olive oil in a non-stick skillet over medium heat, pour in the egg whites, and cook undisturbed until set like a large crepe.
Slide the egg white sheet onto a cutting board and slice into thin ribbons or bite-sized squares.
In the same skillet, lightly toast the pine nuts for 1-2 minutes until golden and fragrant.
In a large bowl, whisk together the lemon juice, Dijon mustard, sea salt, and black pepper to create a bright dressing.
Add the chopped lettuce, sliced cucumber, cooked pasta, and egg white ribbons to the bowl; toss gently to coat.
Transfer the salad to a plate and top with the halved soft-boiled egg and toasted pine nuts.