Place the beef, garlic, ginger, oregano, cumin, paprika, red pepper flakes, ½ teaspoon kosher salt, and ¼ teaspoon black pepper in a bowl. Use your hands to mix, ensuring all of the ingredients are well distributed. Divide the spiced beef into six equal portions. Form into ovals (kofta) and thread each onto a skewer. Set the beef kebabs on a plate and allow to chill in the fridge for 30 minutes to 1 hour.

While the beef is chilling, make the tzatziki sauce: Slice the cucumber in half lengthwise and use a spoon to remove any seeds. Grate seeded cucumber on a box grater and place grated cucumber in a paper towel, 2 towels thick. Wrap the paper towels around the cucumber and squeeze over the sink, removing as much water from the cucumber as possible. Placed drained cucumber in a bowl and add the yogurt, 1 teaspoon lemon zest, the juice from the lemon, minced garlic, the dill, ⅛ teaspoon salt and ⅛ teaspoon black pepper. Mix until well blended. Taste and add additional salt and pepper, if preferred.

Thread the cherry tomatoes and onion slices onto remaining 4 kebab skewers. Drizzle with olive oil and season with kosher salt and black pepper. Set aside.

If cooking on the stove, warm an oiled grill pan over medium heat. Alternatively, heat a grill to medium, oiling the grate and positioning the coals to allow the meat and veggies to cook over indirect heat. Add the kofta and veggie kebabs to the grill and cook until nicely charred on all sides, turning often, 10–20 minutes in total. Brush both sides of the pita bread lightly with oil and add to the grill to warm.

Serve the kofta and veggie kebabs along with the warm pita bread, bibb lettuce and tzatziki sauce.