In a small bowl combine mint, lemon peel, 2 tsp. lemon juice, olive oil, 1/4 tsp. salt, and 1/8 tsp. of pepper; set aside. In a medium saucepan bring 4 cups salted water to boiling.
For cucumber tzatsiki, peel and grate half the cucumber. Cut the remaining cucumber into bite-sized chunks; set aside. Squeeze grated cucumber to remove excess water. In a small bowl combine grated cucumber, yogurt, remaining 2 tsp. of lemon juice, 1 tsp. of garlic, and remaining 1/4 tsp. of salt; set aside.
Halve any large chicken tenders. In a shallow bowl combine chicken, cornstarch, 1 Tbsp. dry sherry, remaining 2 tsp. garlic, 1/2 tsp. salt, and 1/8 tsp. pepper. Stir until cornstarch is no longer visible. Stir in 1 Tbsp. of peanut oil; set aside.
Heat a 14-inch flat-bottomed wok or 12-inch stainless-steel skillet over high heat until a bead of water vaporizes within 2 seconds of contact. Add orzo to the dry wok; stir-fry 1 to 2 minutes or until browned. Remove orzo from pan; transfer to boiling water. Cook 9 minutes or until tender. Drain; set aside.
Meanwhile, add 1 Tbsp. peanut oil to pan. Add chicken; spread evenly in a single layer. Cook, undisturbed, 1 minute, until chicken begins to sear. Stir-fry 1 minute or until chicken is just opaque. Swirl in remaining 2 Tbsp. of dry sherry; stir-fry 1 to 2 minutes or until chicken is cooked through. Add tomato wedges; stir-fry for 30 seconds. Remove pan from heat. Stir in cooked orzo and reserved cucumber.
Drizzle with the mint mixture. Serve with cucumber tzatsiki.