Halve the cherry tomatoes and roughly chop the baby spinach to prepare for the scramble.
In a medium mixing bowl, whisk together the whole eggs, liquid egg whites, sea salt, and black pepper until the mixture is uniform.
Place a non-stick skillet over medium heat and add the extra virgin olive oil.
Add the cherry tomatoes to the hot skillet and sauté for 2-3 minutes until the skins begin to blister and soften.
Stir in the chopped baby spinach and cook for about 1 minute until it is just wilted.
Pour the egg mixture into the skillet, allowing it to sit for 10-15 seconds until the bottom begins to set.
Using a silicone spatula, gently push the eggs from the edges toward the center to create large, soft curds.
When the eggs are mostly cooked but still look slightly wet, sprinkle the crumbled feta cheese evenly over the top.
Remove the skillet from the heat immediately, garnish with freshly chopped chives, and serve while warm.