Toasted Freekeh and Salmon Salad

Name: Toasted Freekeh and Salmon Salad
Ingredients: 2 cups cracked freekeh; ½ large onion; 1 head garlic, halved crosswise; 2 sprigs thyme; 1 sprig rosemary; 1 bay leaf; Kosher salt; 1 pound skin-on center-cut salmon fillet, pin bones removed; 1 tablespoon vegetable oil; ½ cup olive oil; 1 teaspoon finely grated lemon zest; ¼ cup fresh lemon juice; ¼ cup plain whole-milk Greek yogurt; 4 Persian cucumbers, cut into rounds; ½ cup finely chopped fresh dill; ½ cup finely chopped fresh mint; ½ cup finely chopped fresh parsley; An 8 square piece of cheesecloth