Chilies have oils and if you get it on your skin, contacts (ouch!) they will irritate them. To make sure things don't go badly
(1) use rubber gloves
(2) never touch face, eyes but if you do wash with soapy water not just water (trust me water itself does not work)
Control the heat by
(1) Using larger chunks of chilies. Mincing frees the capsasin compunds so it makes things hotter (if that is what you want).
(2) adding a bit of sugar or vinegar helps
(3) to mellow the heat, put jalapenos slices in a pan and simmer with 1/2 cup vinegar, 1 cup sugar and 2 cups water. The cooking liquid has a lot of flavor and can be used in different ways for appetizers, chicken, beef and much more