Biopsionics - can the player limit how much healing they do?

Question

A level 1 biopsionic psychic can heal 1+1d6 hit points. What if they want to limit it to some lower value? is there a way to "pull the punch"?

Answer 1

There is no rule to reduce the amount of healing for level 1

The core technique of Psychic Succor reads:

Level-0: The psychic’s touch can automatically stabilize a mortally-wounded target as a Main Action. This power must be used on a target within six rounds of their collapse, and does not function on targets that have been decapitated or killed by Heavy weapons. It’s the GM’s decision as to whether a target is intact enough for this power to work.

Level-1: As level-0, and heal 1d6+1 hit points of damage. If used on a mortally-wounded target, they revive with the rolled hit points and can act normally on the next round.

So the only way to "pull the punch" is to not apply level 1 healing at all and stick to level 0 healing. The psionic rules have nothing else on reducing the effects of the activation of a psionic power. The powers work much like a spell in classical fantasy games, in having a defined effect when you use them.

There is the metapsionics discipline, which can hinder other Psionics using their powers, but none of its powers would reduce the effect of healing, it rather would affect using the power at all, by making you spend more or less psi points to activate your power, take damage from doing so, or having to make a saving throw to be able to do so.

Stars without number is a game with a very "old-school" vibe, and is similar in rules design to the early versions of D&D. It is actively encouraging the DM to home-brew, and extend the system, page 237:

Stars Without Number derives from an old-school gaming tradition where house rules were almost universal. The basic chassis of the game is simple enough and rugged enough to handle all kinds of tweaks and adjustments without collapsing, and it is your sacred and inalienable right to bend the game in any direction you wish if it improves your fun.

So if you wanted some way to be able to do this, you should talk with your DM. In general however, it seems not a match to how the system is set up.