Supreme Commander

you need a boosting partner since no one plays this online anymore, it has to be done in ranked matches.
setting has to be either annihilation or assasination, i recommend annihilation. (because these are the only 2 settings that have all the maps so it will be easier to track )
you start a battle the loosing commander sets up "no fire" from the unit command(if you dont do this both commanders will take too much damage and the game will end in a tie and do not count)
you meet up in a specified area and the winning commander just shoots till the other is dead, rinse and repeat on all other maps.
you can increase game speed to make it go faster.

Thanks to a tip from a friend before I started this, I can now confirm you don't need another player for the two online achievements. They can be done against the AI in a private online match. At first I had two Supreme AIs on my team, against a Normal AI, but I've found it's not necessary at all to have anyone on your team, as the normal AI is really easy to beat.

Play on Assassination as the UEF(United Earth Federation), have the AI be Cybran, as their ACU has the lowest amount of HPs of the factions. Build an Air Factory, and move its output queue over to the AI's base, you can do that by selecting the Air Factory after it's built, and holding RB and pressing A at the point where you want them to go. So then the Bombers you keep making will automatically head over there and attack the AI ACU. That's pretty much it, I also built some Engineers to help assist to speed up the Bomber production, and build some more Power, but I'm not really sure it's absolutely necessary, as on the fastest game speed the maps take 3-4 minutes at the most anyway.

Here are the 34 MP maps.

Ambush Pass
Arctic Refuge
Bermuda Locket
Blasted Rock
Burial Mounds
Canis River
Concord Lake
Crossfire Canal
Drake's Ravine
Emerald Crater
Fields of Isis
Finn's Revenge
Four-Corners
Four-Leaf Clover
High Noon
Ian's Cross
Open Palms
Paradise
Roanoke Abyss
Saltrock Colony
Sentry Point
Seraphim Glaciers
Seton's Clutch
Sludge
Sung Island
Syrtis Major
The Ditch
The Scar
The Wilderness
Theta Passage
Varga Pass
Vya-3 Protectorate
White Fire
Winter Duel