1 - place shrimp in a small bowl with lid, sprinkle with all the chili powder and salt. Place lid on bowl, and shake so that all shrimp are covered evenly. Set aside to marinate, in the refrigerator, for about an hour   2 - toss thinly sliced onions and peppers together. Heat iron skillet until very, very hot. Once skillet is smoking hot, add oil. Proceed to quickly cook onions and peppers on hot skillet, stirring often until onions start to brown, remove from skillet and place in holding bowl.   3 - without cleaning, cook shrimp in the same pan. As it sizzles and cooks, turn the shrimp that appears to be glossy. The whole process will take about 1 1/2 min., Remove to same holding bowl as onions and peppers. (Shrimp will not be fully cooked yet)   4 - place one tortilla at a time onto the same skillet. When the top of the tortilla starts to bubble, turn. After a few seconds remove to plate, and sprinkle with grated cheese.   5 - while cheese is melting on tortilla, crush garlic over shrimp/onion mixture. Return this mixture to the hot pan and toss until garlic and shrimp are fully cooked, about 45 seconds.   6 - when complete, put half the mixture on each tortilla. Keeping mixture to one side, fold blank side of tortilla over the shrimp mixture. Cut quesadilla to desired handling shape, eat!  

Optional - serve with guacamole and sour cream.