Indian Edamame Quinoa Burgers

Name: Indian Edamame Quinoa Burgers
Ingredients: ½ cup quinoa; 1 cup water; 8 ounces frozen edamame (about 1 1/2 cups), thawed; 3 scallions, chopped, divided; 1 large egg; 1 tablespoon minced fresh ginger; 1 ¼ teaspoons garam masala; ½ teaspoon salt plus 1/8 teaspoon, divided; ¼ teaspoon cayenne pepper; 2 tablespoons extra-virgin olive oil, divided; ¾ cup low-fat plain yogurt; ½ cup chopped English cucumber; ¼ cup chopped fresh cilantro (optional); ¼ teaspoon ground pepper; 1 very large tomato, cut into 4 thick slices