Bison Souvlaki Skewers

Name: Bison Souvlaki Skewers
Ingredients: 1.5 pounds bison skirt steak; 3 tablespoons olive oil; 3 tablespoons lemon juice; 3 teaspoons finely shredded lemon zest; 3 cloves garlic, minced; 1 teaspoon salt; 0.5 teaspoon dried oregano; 0.25 teaspoon black pepper; 25 to 30 6- to 8-inch skewers*; 2 cups plain Greek yogurt; 1 cup peeled, seeded, and diced cucumber; 2 tablespoons thinly sliced green onion; 2 cloves garlic, minced; 0.5 teaspoon salt; 0.125 teaspoon black pepper