In a bowl mix together cream cheese, lemon zest, dill and vinegar. Set aside.
Avocado Spread
Mash avocado in a separate bowl and add salt as desired. Squeeze just a small amount of lemon juice over the top to help the avocado maintain its color
Cucumber Sandwich
Peel cucumber and thinly slice with a mandolin slicer. The thinner the slices the better. Sprinkle cucumbers with salt. Set sliced cucumbers to soak in a small bowl with 1 Tbsp. of lemon juice.
Place two slices of bread on top of one another and cut off the crusts for a true tea sandwich.
Take the top slice of bread and spread the cream cheese mixture on top- as thickly as desired. On the bottom slice spread the avocado mixture.
Remove the cucumbers from their lemon bath and layer on the sandwich. Cover and slice into quarters. Repeat with next sandwich.