Prepare the marinade of olive oil, soy sauce, and lemon juice, and soak chicken for 30-60 minutes at room temperature.
While chicken is marinating, prepare the awesome dill tzatziki. Pulverize cucumber in food processor and strain excess water. Combine the remaining cucumber pulp and other awesome dill tzatziki ingredients in a bowl. Save some for next time or for other recipes.
Skewer the chicken, alternating with red bell pepper and red onion. Grill the kebabs on medium-high heat for 5 minutes, rotate and grill for another 5 minutes.
Wrap naan in aluminum foil and place on grill with kebabs for 5 minutes.
Plate with the naan at the base, lettuce, deconstructed kebabs, cucumber, tomato. Top with optional ingredients and 4 tbsp of tzatziki per souvlaki.