Simple answer: No, you don't have to peel a cucumber. Some people say cucumbers have a bitter skin, and that's why they prefer to peel it. Personally, I never thought it was bitter. Most of the cucumber is water, and many of a cucumber's nutrients are in its skin. So eating the cucumber's skin is a great idea -- especially if you have cucumbers in your garden that you grow organically. If you buy regular cucumbers at your local grocery store, you don't know if chemicals or pesticides have been sprayed on the skin. So, our rule of thumb is if we're eating the skin of fruits or vegetables (like cucumbers, tomatoes, etc.), we buy organic. If we're not eating the skin (like oranges, bananas, etc.), we don't buy organic. If you want to save some money and buy non-organic cucumbers, but still want to eat the skin, that's fine. Just be sure to clean it well with something like a veggie wash (or just really well in the sink).