In a large bowl, add the turkey, garlic, spinach, red pepper, bread crumbs, feta, 1 tablespoon olive oil, oregano, salt and pepper. Gently mix (your hands are best!) until the ingredients are dispersed throughout the turkey. Form into burger patties or sliders (it really depends on the size of your buns! This can make 4 to 6 burgers or 6 to 8 sliders.