Following is my recipe for Greek chicken souvlaki and Τzatziki Sauce. I have added tomatoes, bell peppers and red onion to the skewers, but many traditional souvlaki restaurants serve it with the meat only. Serve it on its own, or tuck the meat inside a pita bread with the sauce, tomatoes and red onion.
Marinade: Cut the lemon in half and add lemon juice to a mixing bowl. Add the wine, chopped oregano and lemon zest, followed by the garlic-shallot puree (or garlic). Slowly pour the olive oil into the marinade and whisk quickly until it starts to thicken.
Marinate chicken 1-2 hours in the refrigerator. When ready to cook, let sit at room temperature about 20 minutes.
Make the sauce by combining ingredients well. Place in the refrigerator until ready to use.
Preheat the grill to 375-450°F.
Place chicken cubes on skewers, alternating with the tomatoes, red onion and bell peppers.
Grill chicken skewers for 5 minutes on each side side, or until chicken is cooked to a temperature of 165 degrees F.
Remove chicken from grill. Sprinkle with paprika and serve in pitas with sliced tomatoes, red onion and the garlic yogurt sauce or tzatziki sauce.