In a food processor, combine the smoked salmon and Greek yogurt. Pulse until smooth and creamy.
Add the dill, chives, lemon zest, lemon juice, and smoked sea salt. Pulse again for about 30 seconds to fully incorporate.
Arrange the cucumber slices on a serving platter. Spoon the salmon mousse onto each cucumber round. For a more polished presentation, transfer the mousse into a pastry bag and pipe it onto the cucumber slices.
Garnish with extra chives and microgreens, if using. Serve immediately and enjoy!