In a large bowl, combine the shrimp with the olive oil, lemon juice, zest, garlic, red pepper flakes and a big pinch of salt and pepper. Stir and let sit for 10 minutes.
Heat the butter in a large skillet (I like a 12 inch) over medium heat. Once melted, stir in the orzo. Cook, stirring often, until the orzo is slightly golden and toasty. Stir in the garlic and cook for 30 seconds.
Pour in the chicken stock and bring it to a boil. Reduce it to a simmer and cover the pot. Cook until the orzo absorbs the water and is fluffed up, about 12 to 15 minutes.
Add in the shrimp to the orzo and stir. Cover the pot again and cook for another 5 to 8 minutes, or until the shrimp is pink, opaque and cooked through.
Sprinkle with fresh parsley and a spritz of lemon. I like to stir in another 1 to 2 tablespoons of melted butter for optimal flavor, but this is up to you. Serve immediately!