Kofte Burger with Harissa and Yogurt

Name: Kofte Burger with Harissa and Yogurt
Ingredients: 1 pound 80/20 ground beef; 1/2 large yellow onion, small-diced; 1 tablespoon ground coriander; 1 tablespoon ground cumin; 1 tablespoon sumac; 1/2 tablespoon cayenne; Salt and pepper; 1 cup Greek yogurt; Zest and Juice of 1 small lemon; 1 tablespoon finely chopped garlic; 1/2 tablespoon ground cumin; 1/2 bunch cilantro, finely chopped; 1/2 bunch dill, finely chopped; 1/2 bunch mint, finely chopped; 1 seedless cucumber, diced; 4 burger buns; Harissa, for spreading; Small handful arugula; 4 sprigs flat-leaf parsley