Combine the spinach, scallion, garlic, turkey, cumin, salt, and pepper in a mixing bowl. Use a fork to gently combine the ingredients.
Heat a large skillet on medium while you form the turkey mixture into about 12 patties, each 1/2" thick.
Add the olive oil to the pan and carefully cook the patties, being careful not to overcrowd the pan. Work in batches and cook them for about 5 minutes on each side, until the patties are golden brown. Try not to push down on the slider while cooking; it may cause them to fall apart.
Use a thermometer to check that the slider have reached an internal temperature of 165 degrees F. Transfer to a plate and top patties with a sprinkle of cheddar cheese. Cover the plate with tin foil to melt the cheeese.
Serve sliders on a bun or toast with sliced tomato