Wash the meat, dab dry and cut into thin strips. Peel garlic and press it through a garlic press. Mix half with gyros spice and oil. Mix with the meat and chill for at least 30 minutes.
For the tzatziki, peel and finely dice the onion. Wash the cucumber, peel if necessary and slice into fine sticks. Mix yoghurt, half cucumber, onion and the rest garlic. Season to taste with salt and pepper.
Cook the rice in about 1/4 l boiling salted water according to the instructions on the packet. Clean or peel and wash the vegetables and salad, cut finely and mix with the rest of the cucumber.
Heat a coated pan without fat. Fry the meat for about 5 minutes. Season with salt and pepper if necessary. Arrange on rice and salad. Add tzatziki. Sprinkle with chili flakes.