Cook the grains: If you haven’t already, cook quinoa, farro, or brown rice according to package instructions. Fluff and set aside.
Make the yogurt-tahini sauce: In a small bowl, whisk Greek yogurt, tahini, lemon juice, water, grated garlic, and a pinch of salt until smooth.
Adjust thickness with more water if needed. Chill.
Prep the shrimp marinade: In a bowl, combine 2 tablespoons olive oil, lemon zest, half the lemon juice, minced garlic, oregano, smoked paprika, cumin, red pepper flakes (if using), salt, and a few grinds of pepper. Add shrimp and toss to coat.
Let sit 10–15 minutes while you prep the vegetables.
Chop the veggies: Halve the cherry tomatoes, dice the cucumber, thinly slice the red onion, and chop the herbs. Set aside the olives and crumble the feta.
Cook the shrimp: Heat a large skillet over medium-high. Add 1 tablespoon olive oil.
Arrange shrimp in a single layer and cook 1–2 minutes per side until pink and opaque. Do not overcook. Squeeze the remaining lemon juice over the shrimp and remove from heat.
Build the plates: Add a handful of spinach or arugula to each plate or bowl.
Spoon on a scoop of grains. Top with shrimp, tomatoes, cucumber, onion, olives, and herbs. Sprinkle with feta.
Finish with sauce: Drizzle the yogurt-tahini sauce over the top.
Add a final swirl of olive oil and a pinch of salt and pepper if you like.
Serve: Enjoy warm right away, or let cool and pack for lunch.