Any 1 v 1 multiplayer map can be updated to support the Tournament scoring system with some simple triggers.
Whether that map would be a "good" map for tournaments is another matter
The How
Tournament Games using the PBEM++ system work by the game reporting out a pair of scores at the end of each turn, one for each player. These are then captured by the server and used to update the scoreboards you see here.
For Order of Battle, each map is scored up to a maximum of 100 points.
To do this in the Editor, you use the Set Scenario Variable trigger effect to updated a pair of variables which the game then reads from in order to report the scores.
These are:
P1TournamentScore
&
P2TournamentScore
P1 is the player that is set to START FIRST.
To see this in action, you can look at any of the maps listed here in the editor: viewtopic.php?f=620&t=100233
As a guideline, you should update these scores any time that something happens in the map that is linked to your scoring system for that map. And you should take extra care to update them whenever someone Wins.
The Why
Not all maps are a natural fit for Tournament Scoring. Order of Battle's systems are quite liberal with how players can recruit, reinforce and disband their units, so just tracking "who's killed the most" is rarely a good system (though I can see cases where it would be appropriate as a sub-objective). Similarly, maps which feature objectives which only change hands at the end of the game (e.g Dubno Fields) aren't really appropriate as there's nothing to report a score against for most of the turns.
Ideally, your map will have some feature which will generate a potential change in score on every turn and will reward and encourage players to keep playing their turns, even if things are turning against them (our tournament system will punish quitters and stallers, but it's better if our maps rewards engagement rather than relying on punishments).
Don't be afraid of designing a map that isn't perfectly balanced, or is very much attack vs defence. All the maps are played as Paired Games with each player playing both sides, so as long as there's a reasonably fair contest, that's usually enough to allow the better players to do well.
However, you should ensure that both sides in your map have a way to "Win" and score the perfect 100 points either through completing objectives or even just holding out as the defender in an invasion map.
Extra Tips
There is a Template map here: viewtopic.php?f=374&t=102015
As you may be updating some scores regularly and some irregularly (e.g. Some are at start of turn, some at special events, some at end of game), it is a sensible precaution to disable sets of triggers once you are sure that you don't want them to feature.
As an example, in Peninsula Invasion, when the Japanese player takes their Primary Objective, I disable all the turn-by-turn and other flag capturing VP award triggers, just to ensure that I'm not double counting anything.
My hope is that we can include the best user created maps with future patches and then run tournaments based on those maps!