1) Yes. MoTL is a "no action" so you can use it at any time.
2) You do get to spend a healing surge if the result is boosted to 20 or higher. It just says you need to roll a 20 or higher, not a natural 20. However, this is not the same as "triggering your second wind." You expend the healing surge and regain hit points equal to your healing surge value, but you don't gain any other benefits of the second wind (such as +2 to defenses), you don't expend the use of your second wind (so if you haven't used it yet this encounter you can still use it later) and you can still spend the healing surge even if you've previously used up your second wind.
