This requires SKSE:
UI.InvokeString("MapMenu", "_global.skse.OpenMenu", "MapMenu")
Or as a helper function:
;/*
* Opens a UI menu by invoking a string. Requires SKSE
* Example for asMenuType is "InventoryMenu"
*
* UI.InvokeString example usage:
* {Opens the Map Menu}
* UI.InvokeString("MapMenu", "_global.skse.OpenMenu", "MapMenu")
*/;
function OpenMenu(string asMenuType, string asMenuName = "HUD Menu", string asTarget = "_global.skse.OpenMenu") global
UI.InvokeString(asMenuName, asTarget, asMenuType)
endfunction