Spicy Lamb and Lentils with Herbs

Name: Spicy Lamb and Lentils with Herbs
Ingredients: 1 tablespoon vegetable oil; 1/2 pound ground lamb; Kosher salt, freshly ground pepper; 2 garlic cloves, thinly sliced; 1 teaspoon crushed red pepper flakes; 1/2 teaspoon cumin seeds; 1 1/2 cups cooked brown or French green lentils (from 1 cup dried); 1/2 English hothouse cucumber, chopped; 1/2 cup chopped fresh cilantro, plus leaves for serving; 1/4 cup chopped fresh parsley, plus leaves for serving; 3/4 cup plain whole-milk Greek yogurt; Flatbread and lemon wedges (for serving)