Fill a shallow pan with at least 3 inches of water. Add the white vinegar; bring the water to a boil and then reduce to a simmer.
Equally divide the microgreens among 4 small plates. Squeeze a touch of lemon juice on each pile of greens.
Lay 2 ounces of the smoked salmon on top of the greens.
Cut the avocado in half lengthwise. Remove the pit from the avocado and discard. Remove the avocado from the skin, place the avocado on a cutting board, and cut into thin slices. Put the avocado slices on top of the smoked salmon and add another squeeze of lemon juice.
Crack an egg into a small prep bowl. Carefully slip the egg from the prep bowl into the poaching water. With a spoon, nudge the egg white together so the egg remains as close together as possible. Repeat this for the remaining 3 eggs.
Cover the pan with a tight-fitting lid and turn off the heat. Let the eggs cook for 3 to 4 minutes, then carefully remove each egg with a slotted spoon, letting any excess water drip off. Transfer the egg to the top of the avocado and smoked salmon.
Season with salt and pepper, and serve immediately.
Prep time: 10 minutes
Cook time: 5 minutes
Yields: 4 servings