For the aioli:
½ teaspoon ground cumin
½ teaspoon ground coriander
½ cup mayonnaise
2 tablespoons extra virgin olive oil, plus more for brushing
2 teaspoons fresh lemon juice
1½ teaspoons smoked paprika
1 garlic clove, minced
For the burgers:
1 pound ground turkey
1 small red onion, sliced into 4 ⅓-inch slices
4 hamburger buns
Arugula, for topping
To make the aioli, whisk mayonnaise, olive oil, lemon juice, garlic and spices together in a small bowl. Add salt and pepper to taste.
Place turkey in a medium bowl and gently mix in 2 tablespoons aioli. Form into 4 equal patties and use your thumb to form a small indention into the center of each. Heat a grill pan to medium-high heat. Brush onions with olive oil and sprinkle with salt and pepper. Grill for 4 minutes per side. Brush burgers with olive oil and sprinkle with salt and pepper. Grill for 5 minutes per side.
Place burger on bun and top with aioli, grilled red onion and arugula.