Mix soy sauce and apple cider vinegar in a bowl, add the salmon fillet and let it marinate for at least 10 minutes. Then place the salmon fillet on a baking sheet and cover it with the rest of the marinade sauce.
Cover the salmon fillet with chopped tomatoes, sliced red onion, capers, black olives, parsley and lemon zest. Add olive oil, half lemon juice, and salt to taste.
Bake in pre-heated oven at 200 degrees for 15/20 minutes. Enjoy with a salad or baked potatoes as a side!