In a large salad bowl, add the salmon, cucumber, tomatoes, red onions and green onions. Mix everything together until combined.
In a mason jar, pour the freshly squeezed lemon juice and olive oil. Add salt and pepper and whisk everything. Continue to whisk while streaming in the olive oil*.
Taste to check the seasoning and pour over the salad. Enjoy!
Notes
To make the salmon: Preheat the oven to 400°F. Line a baking sheet with parchment paper or silicone mat. Place salmon on the baking sheet, skin-side down, season with salt and pepper and bake 10 to 12 minutes. Remove from the oven and let it cool down. Flake flesh and set aside.
If you do not want to cook fresh salmon, you can use canned salmon.
Try to use freshly squeezed lemon juice as bottled juice does not have the same bright taste.
Make sure everything is chopped into uniform bite-sized pieces so you're able to get a bite of everything with each forkful.
To store: Store leftover salmon in the fridge in an airtight container for up to 4 days. This dressing stays good in the fridge in a sealed container for about a week.
To freeze: Freeze cooked salmon in a freezer-safe bag once the fillets have reached room temperature. Freeze for up to 4 months.