If using frozen spinach, thaw it and squeeze by hand to remove as much liquid as possible.
Saute onion in oil until translucent. Add garlic, carrots, corn, herbs, and spices. Saute until vegetables are tender. Reduce heat to low and add spinach. Stir just until the spinach is warm. Set aside.
Coat a skillet with oil and heat to medium high. Add a tortilla and cover with 1 cup of cheese and 1/4 of the spinach mixture. Fold the tortilla in half when the cheese begins to melt. Turn until both sides are brown. Repeat with the remaining 3 tortillas.