In a medium bowl, combine shrimp, 1 tbsp olive oil, lemon zest, red pepper flakes, 1/2 tsp salt, 1/4 tsp pepper, and half of the minced garlic. Let marinate for at least 10 minutes (or up to 1 hour).

In a medium skillet, heat butter and the remaining 2 tbsp olive oil over medium heat. When the butter bubbles, add the orzo and toast it for about 2 minutes, stirring frequently. Add the remaining minced garlic and cook for 1 more minute.

Carefully pour in the white wine (it will bubble) and stir until mostly absorbed, about 1 minute. Stir in the boiling water or stock, reduce the heat to low, cover, and let cook until the orzo is al dente, about 12-16 minutes. Stir occasionally to prevent sticking.

Arrange the shrimp in a snug, even layer on top of the orzo. Cover and cook until the shrimp are pink and opaque, about 2-4 minutes. Remove from heat and let sit, covered, for 2 minutes.

Mix in the lemon juice, starting with 1 tablespoon and adding more if desired for a stronger citrus flavor. Sprinkle parsley or chives over the top to garnish. Season to taste with additional salt and pepper if needed. Serve immediately with extra lemon wedges on the side.