Grind together coriander powder, cumin powder, garam masala powder, ginger-garlic paste, black pepper, salt, dry fenugreek leaves and red chili powder to a fine paste. Put the paste aside.
Chicken
Remove skin from the chicken. Make deep cuts on both sides of the chicken.
First marinade
Mix together red chili powder, turmeric powder, and lemon juice. Apply this mixture to chicken pieces rubbing it into the deep cuts of the chicken. Cover the chicken and put aside to marinade for 15 minutes.
Second marinade
Mix the Tandoori paste with yoghurt into a smooth sauce.
Pour the mixture onto the chicken covering each piece on both sides, allowing mixture to get into the deep cuts of the chicken. Mix together apple cider vinegar and oil and sprinkle onto the chicken pieces. Cover and refrigerate for 4 hours.
Pre-heat oven to 225°C (437°F). Remove the chicken pieces from refrigerator and lay them on an aluminum tray/foil. Put them uncovered on the middle rack of the oven for 25 minutes. After 25 minutes in the oven, put them in a broiler and broil each side for 3 minutes.
Garnish this tandoori chicken with thinly sliced raw onion and lemon or lime, cut into wedges, and serve with Naan bread.