1. For the cashew queso: Soak cashews in water for at least 4 hours or overnight. If you have a high-powered blender you can skip the soaking step.
2. Heat water, but don't boil. Peel and chop garlic.
3. Place cashews, hot (but not boiling) water, and remaining queso ingredients into blender.
4. Scraping sides often, blend for 2 minutes, or until smooth and creamy. Set aside.
5. For the fajitas: Preheat oven to 170F or lowest setting.
6. Peel and slice onion. Thinly slice bell pepper. Finely mince cilantro. Chop, slice, or shred cooked chicken.
7. In a small bowl, combine all spices and seasonings to make fajita seasoning.
8. Heat a skillet over medium-high heat and add 1/5 of the oil. Add onions and cook until soft and translucent, 5-8 minutes.
9. Add pepper and cook, stirring frequently, until tender - about 3-5 minutes - depending on how much char you like on your fajita veggies.
10. Add chicken to skillet and sprinkle in seasoning. Stir and cook through until chicken is warm and everything is coated in spices. Sprinkle in cilantro and stir.
11. Remove quesadilla filling to a bowl. This is a good time to portion out filling for each quesadilla you are making to speed assembly.
12. Wipe out skillet and place back on stove. Lower temperature to medium heat and melt 1/4 of the remaining oil in skillet.
13. Place a tortilla into skillet, heat for 1 minute to allow bubbles to form, flip and cook for 30 more seconds, until bubbles form and then flip again.
14. On 1/2 of tortilla, place half of a portion of queso and a portion of chicken and veggie filling. Top with remaining queso.
15. Fold tortilla over and continue to cook until bottom is golden brown, about 1-2 more minutes.
16. With confidence, quickly flip and cook other side for another 2-3 minutes, until golden brown and queso is melted.
17. Remove from skillet and cut into 4 wedges. Repeat with remaining tortillas and filling.
18. If making quesadillas in batches, place them on a wire rack on a baking sheet and put them in the oven to keep warm.
19. Serve with remaining cashew queso for dipping.