Combine all kebab ingredients in a bowl and knead until smooth
Portion the meat into ¼-lb oval shapes and place one on the outside center of a Ziploc bag
Lay a wooden skewer on top and press it halfway into the meat, then fold the bag up and over so the plastic encloses the meat
Use a bench scraper to roll and mold the meat into a uniform cylinder around the skewer
Arrange sliced onions in the center of a sheet pan
Toss potatoes with potato seasoning and line them around the outer perimeter of the pan
Place kebab skewers on top of the onions
Tuck Anaheim pepper halves between the skewers and arrange cherry tomatoes along the inner perimeter
Whisk together tomato passata, olive oil, hot water, and salt
Pour sauce evenly over the entire pan
Bake at 350°F (180°C) for about 30 minutes, until the kebabs reach an internal temperature of 160°F and the potatoes are tender
Broil for 2 minutes to brown the kebabs
While baking, mix all tzatziki ingredients until smooth and chill
Serve kebabs with tzatziki sauce and homemade pita
