Direction :

1. Marinate the chicken. In the bowl of the food processor, purée the garlic and basil into a fine paste. Stop the processor, scrape it down, add a splash of olive oil, and purée again. Transfer the paste to a large bowl. (Alternatively, you can simply roughly chop the garlic and basil.)
2. Cut chicken into roughly 1- to 2-inch pieces. Transfer it to the bowl with the garlic-basil paste. Season chicken all over with kosher salt and pepper to taste — a good rule of thumb is 1 teaspoon (or slightly less) of kosher salt per pound of meat. Crumble oregano (about a teaspoon or two) over top. Add a splash of olive oil. Toss to coat. Cover bowl and transfer to the fridge to marinate for at least two hours if possible. If you don’t have space for a big bowl in your fridge, you can use a ziplock bag. 
3. Cook the chicken. When ready to cook: Preheat the grill to its highest setting (525ºF or 550ºF) or preheat the broiler to high for at least 15 minutes. Skewer the chicken. Season lightly with salt and pepper all over. If grilling, grill skewers for 3 minutes a side or until charred to your liking. If broiling, set the chicken on a lightly oiled broiler pan or a cooling rack set in a sheet pan. Broil 5 minutes. Flip. Broil 4 to 5 minutes more or until charred to your liking. Transfer to a platter. (Optional: smear tzatziki on a platter; then tumble the grilled or broiled pieces of meat over top.) Season lightly with sea salt and squeeze some lemon over top. Let rest at least 5 minutes before serving with more tzatziki on the side, lemon wedges, salad, and warm naan or pita.
4. To make the salad: Place the tomatoes or cucumbers in a bowl. Season all over with salt and pepper to taste. Add a tablespoon of each olive oil and vinegar — use more or less depending on how many tomatoes or cucumbers you are using. Add basil or mint leaves. Toss to coat. Transfer to a platter. Crumble feta over top. Crack more pepper over top.