Preheat the oven to 200C/400F/Gas 6.
Place the chicken thighs into a glass dish, add all the other chicken tikka ingredients (except the onion and olive oil) and mix together well. Leave to marinate for ten minutes, or up to one hour if possible.
Skewer the chicken onto two metal skewers, alternating the chicken with chunks of onion. Drizzle with a little olive oil, heat an ovenproof griddle until smoking hot and add the chicken. Cook for a few minutes on each side, or until lightly charred.
Juice half the lime and drizzle over the chicken. Leave the other lime half whole and add to the pan. Place in a hot oven for eight minutes, or until completely cooked through.
For the rice, cook the brown rice in boiling salted water, according to the packet instructions. Once the rice is cooked, drain.
Meanwhile, melt the butter in a non-stick frying pan, add the onions and cook over a low heat until softened but not coloured. Add the onions to the cooked, drained rice, stir in the carrots, curry powder, sultanas, spinach leaves and lemon juice and zest. Stir well and season.
To serve, pile the rice on a serving plate and top with the chicken skewers. Garnish with lemon wedges.