If a player uses a one-handed weapon with both hands they get 1.5x Strength bonus to damage. Does this bonus apply to combat maneuvers as well? Since there's no such thing as "damage" when it comes to a maneuver, would it boost the CMB? Say a player attempts to disarm using a one-handed Flail with both hands. Would their CMB go up for the attempt?
No, it would not. The damage roll is largely irrelevant when it comes to CMB. The only maneuver where I believe it might make a difference is if you're attempting to Sunder something, but even then it has no effect on the CMB, just the damage.
You don't add to your attack roll when two-handing, so you don't add to your CMB. This also applies when you wield a two handed weapon.
A CMB is basically just an attack roll. In most situations they will be identical.