how early? dnephwe loves cucumbers, with the skin on. its perfect food, because he can hold it, bite it with his gums, and if it is cool, then it is perfect for his teething. and unlike carrots, i dont worry about him choking on it.
I gave dd cucumber from when she was about 8 months, big chunks about 4inches long. She still loves it and will eat a whole one if we let her! We often buy one from the market stall and dd will wander round the market with us chomping on it for ages. (She's 9 now.)