Slice

the halves leave along your line.

swipe an edge through tossed fruit, and not through the bombs

A cut is a direction, not a tap: the blade is the line your finger travels, and when it crosses a fruit the two halves leave along that line's normal, so a fast diagonal throws them apart and a slow graze barely parts them.

Concepts: velocity, direction.

An interactive you play with one thumb, on Wundr.