Make the salad dressing by whisking together the lemon juice, the lemon zest, the extra-virgin olive oil, the Dijon mustard, the minced garlic, the salt, and the black pepper.

Toss the arugula with half the salad dressing and distribute it in two salad bowls (or put it on a serving platter to share).

On top of the arugula, add toasted walnut pieces, soft goat cheese chunks, and chopped avocado.

Add the smoked salmon on top and drizzle the remaining salad dressing over the top.