Our pickling gherkin cucumbers have grown large and become yellow. Can you still safely eat them in salads?
Yes, they are just well over-mature. They are meant to be picked very young, and small. This will affect the flavor quite a bit, but they are definitely edible.
Here is an article for more information: https://www.gardeningknowhow.com/edible/vegetables/cucumber/when-to-pick-a-cucumber-how-to-prevent-yellow-cucumbers.htm