Heat a medium saute pan over medium heat and add the olive oil. Add the baguette slices and toast them in the olive oil until golden brown, approximately one minute on each side.
Remove to a towel-lined plate and lightly season
For the Avocado
Place the ½ avocado in a small mixing bowl and add the lime juice and generous pinch of salt. Using a fork, smash the avocado until smooth. Adjust seasoning with additional salt and lime to taste.
Chill until ready for use.
To Assemble
Spoon a generous spoonful of the avocado puree onto each toast and spread evenly.
Using a Microplane, grate the pistachios over the toast in a dense, even layer.
Generously spoon the caviar over the top of each toast and finish with the cilantro or fresh herbs.