Throw the oil, edamame, spinach, lemon juice, tahini, onion, garlic, cumin, pepper flakes, and salt into your high-speed blender or food processor and blend on high or process for about 2 minutes, until smooth and creamy. Stop the machine periodically and scrape down the sides of the container to fully incorporate the ingredients. (A food processor will give the mixture a coarse consistency, which some people prefer.) Tweak the lemon juice, pepper flakes, or salt to taste.