Turkey Spinach Sliders

Name: Turkey-Spinach Sliders
Ingredients: 1/2 bunch flat-leaf spinach, thick stems removed, leaves chopped (about 4 cups); 4 scallions, thinly sliced; 1 garlic clove, finely chopped; 1 pound ground turkey; 3/4 teaspoon ground cumin; Kosher salt, freshly ground pepper; 3 tablespoons olive oil; 12 slider buns or small dinner rolls, split, lightly toasted (for serving); Mayonnaise, sliced red onion, and pickle slices (for serving)