Place the chicken strips in a large bowl and sprinkle with the lemon juice. Spoon in the tikka paste and garlic and toss together. (If time allows, leave to marinade for 30 minutes at this stage) Heat a large wok or frying pan. Pour in the chicken with its marinade and cook for 5-7 minutes. Season with freshly ground black pepper. Meanwhile blanch the beans in boiling water. Heat a wok with a tbsp of oil and toss in the beans, remove from the heat and toss through the baby spinach leaves. To serve, pile the spinach and beans into the centre of a large serving dish. Top with the hot chicken and drizzle over a little greek yogurt. Serve with warm pitta breads.