Add the cream cheese, crème fraîche, lemon juice, and lemon zest to a food processor. Puree the ingredients until well combined, about 30 seconds.
Mince the chives and dill. Roughly chop the smoked salmon.
Add the minced chives, minced dill, and roughly chopped smoked salmon to the cream cheese mix in the food processor. Puree just for 10 seconds until combined. Don’t overprocess it. Taste it and add a pinch of salt to taste (if needed). If adding salt, puree the spread for a couple of seconds just to mix the salt it. Cover it and refrigerate it while making the crostini.
Make the crostini. Cut the baguette into 1/2-inch slices and brush each slice on both sides with olive oil. Grill the bread on a grill, grill pan, or electric grill for a couple of minutes on each side. Alternatively, you could bake the bread slices at 360°F (180°C) until golden brown (about 10-12 minutes).
Serve the smoked salmon dip with the crostini or with baguette slices.