1. Place the spinach in a large bowl and cover with clingfilm. Microwave on high for 2 minutes until wilted then cool and squeeze out the excess liquid. Place in a food processor with the remaining falafel ingredients. Process until it forms a coarse paste, season well.
2. Divide the mix into 24 and, with damp hands, roll into balls. Chill for 30 minutes. Heat a little oil in a large frying pan and fry the falafels in 2 batches for 5-6 minutes, turning occasionally, until golden. Thread 3 falafels onto each of the 8 wooden skewers.
3. Meanwhile, halve the cucumber lengthways, scrape out the seeds and slice. Mix in the mint, yogurt and seasoning. Serve with the skewers.