Combine soy sauce, ginger, olive oil, and pepper in a bowl. Toss with chicken, cover and place in the fridge for at least 30 minutes to marinate.
While chicken is marinating, immerse bamboo skewers in water to soak to lessen the chance of burning the skewers when on the grill.
Finely dice 1/4 cup cucumbers.
Combine diced cucumbers with garlic, dill, salt, pepper, and yogurt. Stir gently to combine. Place in fridge until time to serve.
Heat grill to medium heat.
Slide approximately 5-7 pieces of chicken onto each skewer and place on the grill. The olive oil in the marinade eliminates the need to oil grill.
Cook for 5 minutes each side, until chicken is cooked through.
Arrange romaine leaves on a plate, top with sliced cucumbers, chicken, and tzatziki. Finally, garnish with sesame seeds.