Heat a wok on medium heat; add onion and sauté until slightly golden brown (about 5 minutes). Sprinkle water if onion is sticking to the pan.
Bring heat to medium and add spinach, ginger, garlic and salt and sauté until everything is mixed and the spinach cooks down (about 5 minutes).
Lay a tortilla flat and spread spinach mixture along with pepper jack cheese. Cover with the other tortilla.
Heat a wide open flat pan on medium heat; brush some cooking oil on the pan. Lay the quesadilla on the pan until golden brown, then flip and repeat. Once both sides are golden brown, remove from heat.
Slice quesadilla into pieces (like a pizza). Garnish with cilantro and serve hot with chilled vegan sour cream, guacamole and pico de gallo.
Notes
Note: Use gluten-free tortillas to make this recipe gluten-free.