They are readily available in most markets, both fresh and canned. Store fresh peppers in a plastic bag in your refrigerator, where they will keep for up to 1 week. Capsaicin retains its potency despite time, cooking, or freezing, so removing the veins and seeds before using peppers is the only way to reduce the heat. Small peppers have more membranes and seeds than large peppers, so generally they are hotter. To avoid irritation from the caustic oils in chile peppers, do not touch your eyes, nose, or lips while handling them.
Many cooks wear disposable plastic gloves when working with hot chilies.
Afterward, wash your hands, knife, and cutting board in hot, soapy water. Serve these skinny, warm grilled-cheese Mexican sandwiches with a green salad for a light lunch. For an appetizer or soup accompaniment, let the quesadillas cool and cut them into smaller wedges. Heat the oil in a large nonstick skillet over medium-high heat. Taste and adjust the seasoning.