I'm looking at making a fire kineticist who grapples enemies to make the most of the Searing Flesh defense infusion. I noticed that as a part of the standard action to maintain the grapple it is possible to deal damage equal to your unarmed strike. Is it possible to increase this unarmed strike damage using Kinetic Fist while grappling an opponent?
Kinetic fist says:
...You can use this form infusion as part of an attack action, a charge action, or a full-attack action...
Damage: You can inflict damage to your target equal to your unarmed strike, a natural attack, or an attack made with armor spikes or a light or one-handed weapon. This damage can be either lethal or nonlethal.
This is not an attack, charge, or full-attack action, but a standard action, requiring a grapple check.
The grappled condition, which both grapplers have, causes
...a –2 penalty on all attack rolls [... and a] grappled character who attempts to cast a spell or use a spell-like ability must make a concentration check (DC 10 + grappler's CMB + spell level), or lose the spell...
So you can attack, but at a penalty, and you must successfully concentrate.