Preheat the oven to 180°C (356°F).
Slice the baguette or whole wheat bread to an appropriate thickness.
Lightly brush olive oil on the bread.
Bake the bread in the oven for 5 minutes.
Finely chop cucumber and onion.
In a bowl, combine Greek yogurt, cucumber, minced garlic, lemon juice, dill, salt, and pepper. Mix well to make tzatziki sauce.
Spread a generous amount of tzatziki sauce on the toasted bread.
Arrange smoked salmon nicely on top.
Slice cherry tomatoes and red onion, then place them on the salmon.
Finish by garnishing with dill and pepper.