Preheat oven to 375 degrees F and have ready a large baking tray.
Peel and roughly chop the onion. Put the onion and the garlic in a processor and blitz until it is minced fine. Remove from food processor and wipe clean.
Add the mint leaves to the food processor and blitz until finely chopped. Remove from food processor and set aside.
In a medium skillet set over medium heat, add about 2 tablespoons of the olive oil. Add the minced onion and garlic and give a good stir. Cook stirring occasionally for about 10 minutes. Add the coriander, cumin, red pepper flakes and salt. Stir for a minute and remove from heat.
In a large bowl combine the chicken, onion mixture and mint. Stir well to combine completely.
Have ready 10 wooden skewers.
Using your hands, scoop up a small ball sized portion of the mixture. Push it onto the top of the skewer and start flattening it out with your hands and pushing it down the stick. It should cover about 2/3 of the stick. Repeat for all sticks.
Place a large baking tray in a preheated 375 degree F oven for about 10 minutes. Remove from oven and drizzle the tray with remaining olive oil. Place the skewers on the tray and put in the oven. Cook for 15 minutes and remove from oven and turn them over. Return to oven for remaining 15 minutes or until cooked through.
Remove from oven and serve straight away.