In a bowl, combine lemon juice, dill, olive oil, salt and pepper. Lay salmon in the bowl and allow to marinate for at least 20 minutes (you can even do this the night before).

Preheat oven to 375 degrees F. Place salmon fillet in an ovenproof dish, pouring the marinade over top. Bake for 25 minutes — the salmon should flake apart.

Place on a bed of arugula and cucumber, spooning the dill/lemon juice mixture on top.