Preparation:

Preheat skillet to medium. Heat canola oil. Add garlic and cook until softened, about 3 minutes. Add onions and peppers, cooking until very soft, about 10 minutes.  

While peppers are cooking, mix chili powder, salt, sugar, red pepper flakes, and cumin in small bowl. Add 2 tbsp water and mix thoroughly. Add to peppers mixture in pan. Add shrimp, cooking just until pink through and sauce reduces, approximately 3 minutes. Reduce heat to low.

While shrimp is cooking, mash avocados until smooth. Add sour cream and lime juice, mixing thoroughly. Place 1/8 chicken and peppers mixture into each tortilla. Spoon 1/8 avocado aioli over each tortilla. Fold over and serve, two fajitas per serving.