Season shrimp with salt and pepper. In a large skillet over medium-high heat, add 1½ tablespoons olive oil. When shimmering, add shrimp in a single layer and cook for 1-2 minutes per side until pink and just opaque. Remove to a plate and cover loosely with foil to keep warm.
In the same skillet, add remaining olive oil. Add the orzo and cook for 2-3 minutes, stirring frequently, until lightly golden.
Add minced garlic to the toasted orzo and cook for 30 seconds until fragrant. Pour in the stock, lemon zest (reserving a pinch for garnish), and red pepper flakes if using. Bring to a boil, then reduce heat to maintain a simmer. Cook uncovered for 8-10 minutes, stirring occasionally, until orzo is tender and most liquid is absorbed.
Stir in cherry tomatoes and cook for 1 minute. Return shrimp to the skillet along with half the herbs and lemon juice. Gently fold everything together until warmed through, about 1-2 minutes.
Remove from heat and top with crumbled feta cheese and remaining fresh herbs. Serve immediately.