Preheat your grill to a medium-high heat. Clean and oil grill grates. If you’re using wooden/bamboo skewers, immerse them in warm water to prevent them catching on the grill.
In a large bowl, mix together the garlic, oil, red pepper flakes, lemon zest and juice, maple syrup, salt and pepper.
Prick chicken thighs all over with a fork, then cut into two-inch chunks. Add to the marinade bowl and mix to coat. It only needs to sit for around five minutes.
While the chicken marinates, make the chimichurri : add all ingredients to a food processor and pulse until the herbs are coarsely chopped. Check seasoning to taste. Leave at room temperature until the chicken is ready.
Thread the chicken onto metal (or pre-soaked bamboo) skewers. Make sure to leave a little room between pieces on the skewers so they cook evenly.
Thread the tomatoes onto separate skewers, brush with olive oil and sprinkle with a little sea salt.
Grill the chicken kebabs until lightly charred and cooked through, turning skewers occasionally. This should take around 10 minutes.
Transfer the skewers to a platter and serve with the chimichurri sauce.