Put the wooden skewers in a bowl of water to soak. Finely grate the lemon zest into a large bowl and squeeze in half the juice. Peel and grate the garlic. Finely chop the rosemary leaves. Add them to the lemon with the chicken, a good pinch of salt and pepper and 1 tbsp oil. Toss to coat and set aside to marinate for 20 mins.
While the chicken marinates, tip the buckwheat into a pan and pour in enough boiling water to cover the buckwheat by 1 cm. Bring to the boil, then turn the heat down to a simmer. Cover with a lid and cook for 10-15 mins till tender.
While the buckwheat cooks, tear the basil leaves into a large bowl. Squeeze over the remaining lemon juice and stir in 1 tbsp olive oil. Set aside.
Pod the broad beans (see our tip about double podding them). Add them to the basil. Drain the buckwheat and stir that in with a good pinch of salt and pepper.
Heat your grill to high. Use a veg peeler to peel ribbons off the courgette. Roll each ribbon up and thread them onto skewers with the chicken and tomatoes.
Arrange the skewers on a baking tray and grill for 4-5 mins on each side, till golden and cooked through. Serve the skewers with the rocket and the buckwheat salad.