Copying our Neighbour - Cucumbers

A few months ago I saw our Italian neighbour planting cucumber seeds directly into the soil. He rotivated the area, put down a load of compost and spent ages preparing the ground. I copied him but without the preparation and  planted a row of cucumber seeds. We have had about 50 cucumbers so far, mostly short and fat ones with very bitter skin but once you peel them they are delicious. We have used a lot for juicing and given many away to colleagues, neighbours. friends.

Does anyone know if the bitter skin is caused by not growing them properly or is it the variety?

Chicken wrap with home grown cucumber and lettuce

Halloumi with coriander, lime and chilli dressed cucumber