If using bamboo skewers, pre-soak them in water before beginning prep. Peel and slice lengthwise and de-seed both cucumbers. Finely grate 1 whole cucumber. Place in a sieve and press out excess liquid; allow to drain for 15 minutes. Peel and mince garlic. De-stem and chop herbs individually. Slice the chicken breast in 1/2 inch strips against the grain. Place the chicken in a bowl and add the oregano, half the garlic, juice of half the lemon, olive oil, salt and pepper, and stir thoroughly and chill for 20 minutes. In a bowl, combine the yogurt, remaining garlic, strained cucumber, dill and salt and pepper, stire and chill. Dice the tomatoes, the remaining cucumber, and julienne 1/2 the onion, combine in a bowl and stir in olive oil, salt and pepper to taste. Dice or crumble the feta cheese and set aside. Skewer the marinated chicken. Grill the chicken skewers, squeezing the remaining 1/2 lemon over them while grilling. Heat the pita bread. Serve the pita gyro style, layering it with chicken, yogurt sauce, vegetable salad and feta cheese.