I've come across an easy way to come reasonably close to the texture, appearance and flavour of tandoor cooked chicken tikka, and thought I'd share it with you. Here is what I do:
(for one)
Chop a chicken breat into tikka sized chunks. Put them in a bowl, and drizzle with a small amount of oil. Squirt in a teaspoon of garlic purre, 1/2 a teaspoon of turmeric, and 1/2 a teaspoon of paprika, plus a pinch of chilli and red food colouring. Mix well with your hands to evenly coat, and leave for about 30 mins.
To cook, take a nice thick cast iron wok/karahi, and heat a tiny amount of oil to a very high tempertaure. Chuck in the chicken. Proceeed to stir fry. Stir very quickly, else the chicken quickly sticks after a few minutes, the chicken will be sealed, and you can relax a bit. Keep stirring at a slower rate, and keep the heat nice and high. After 5 minutes, or so, you should be getting a hint of charring on a few of the pieces, at this point remove from the heat. If the heat was high enough, the chicken should have JUST turned from pink to cooked. It will be incredibly tender and juicy, and look just like chicken tikka. If you've gotten it to char a bit, it will taste quite like it as well. It is then ideal to chuck into a curry as 'pre cooked' chicken, and serve up. However, you can't cool and re heat it, otherwise you lose the tenderness and juicyness.
Also, dont use more than pinch of chilli powder, or you'll do your throat in when frying it.