Here's a Tip from The Hippy in the Kitchen to eliminate the Bitterness from Cucumbers.
Step 1:
Do not Peel them in the beginning.
Step 2:
Cut off Both ends no more than 1/2" and save the pieces you cut off.
Cut off a thin slice and taste it to check for bitterness.
If bitter, continue through the rest of the steps.
Step 3:
Rub both ends with the piece you just but off and you'll notice a White Creamy Substance being released.
Continue rubbing and wiping off the ends until you don't see anymore of the Creamy Substance.
Step 4:
Use a Potato Peeler and Peel off the Green Peeling. When you remove it, continue around 1 more time and remove a thin layer of the White.
Done! Cut off a thin slice and taste it.
Enjoy!
Peace in the Kitchen!