This open-faced sandwich is reminiscent of what you might find in a cafe in Northern Europe. It's a snap to pull together and works for a breakfast, light lunch, or afternoon snack.
When the toast is done, use the back of a fork to gently mash the avocado on top. Scatter the capers on the avocado, add a generous squeeze of lemon, and a pinch of salt. Lay the cucumber slices on top followed by the smoked salmon.