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by creating a channel of type "web shortcut" with name "/clear-temps".
Note that "clear-temps" can be chosen arbitrarily, because it is the event identifier (EID). Contrast this with the case for queries in which the name fo of the channel must match your ruleset identifier (RID). For events, the RID does not appear in either the longer standard URL nor in the short one.
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Notice that for events, the first part of the path in a shorter link can be chosen somewhat arbitrarily, because it becomes the EID in the (internally) rewritten longer link that actually is seen by the engine. In the case of queries, the first part of the path in the shorter link must exactly match the RID. In both cases, the first part of the path (immediately following the domain name and port (if present)) must match this regular expression: re#/[\/\w.-]*#, i.e. it must begin with a forward slash, followed by letters, digits, or the underscore, period, or hypen characters only.
If you are wondering why the ECI for the secret channel named "admin" is redacted in the image above, it is because this is the only channel that the pico has which is not fungible, which cannot be deleted without requiring the pico itself to also be deleted. So, even though the pico is running on an engine which I control, and which is running on a machine which I control, I'm not taking any chances.
This capability willn't will be introduced into the engine until after its current in version, 0.4344.0 (at which time this paragraph will be removed, so savor it while it lasts).