Pat the shrimp dry and toss them with 1 tablespoon olive oil, the minced garlic, oregano, salt, and pepper in a bowl.
Heat a grill or grill pan over medium-high heat. Grill the shrimp for 2 to 3 minutes per side until pink and lightly charred. Remove from heat and set aside.
In a large mixing bowl, combine the chickpeas, diced cucumbers, halved cherry tomatoes, and sliced red onion.
Whisk together the remaining 2 tablespoons olive oil and lemon juice, then pour over the chickpea mixture. Stir gently to coat.
Add the grilled shrimp and chopped parsley to the bowl. Toss everything together one more time before serving.