Start by marinating the meat. Put the chicken thigh cubes in a bowl and mix with a splash of olive oil, the dried oregano, paprika powder, and some Celtic sea salt. Set the bowl aside and let the chicken rest for at least fifteen minutes.
Meanwhile, make the tzatziki. Grate the cucumber and squeeze out the excess moisture thoroughly. Mix the dry cucumber in a bowl with the Greek yogurt, the pressed garlic clove, and a pinch of Celtic sea salt. Then cut the tomatoes into wedges and drizzle with a little olive oil.
Thread the marinated chicken pieces onto skewers. Heat a grill pan or use a hot barbecue. Grill the chicken skewers for eight to ten minutes until cooked through and golden brown on all sides. Turn them regularly while cooking so the meat cooks evenly and doesn't burn.
Place the warm chicken skewers directly onto plates. Arrange the tomato wedges alongside and add a generous amount of the homemade tzatziki next to the meat to finish the dish.