A waterjet is fast moving water:
waterjet water speed at 40,000 psi = 680 m/s
waterjet water speed at 60,000 psi = 1021 m/s
A pressure washer gives water a speed of 110 m/s.
How fast can a centrifuge spin? Ultracentrifuge speed:
centrifuge spins at 1e5 rpm, has a 10 cm radius rotor.
This give a speed at the rim of:
45 cm rotor circumference at the bottom of the tube
1e5/60 rotations / sec
0.45m/60 x 1e5 = 7.5e2 m/s
So a centrifuge does get water moving fast enough to act as a waterjet.
To turn the rotor spin into a line of water drops, open a door in the bottom of the rotor as the rotor passes a certain point in every spin (1000-2000 times / sec).
If the door is open for 10 us, the rotor will spin 1.5mm.
If the door is open for 1 us, the rotor will spin 0.15 mm.
The water stream will come out in a line, so the resolution in the other dimension can be finer, with the waterjet spread out along the direction of the cut.
A door can’t be mechanically opened and closed that fast, 1 ms is likely the limit.
But a reasonable solution is a rotating (or vibrating) plate with a hole, say spinning 1000/s (or 100/s, opening only every tenth pass), and synchronized with the main rotor spin so opening appeared at the same point along the edge. This would tend to torque the main rotor, but it might be tolerable.
This would give a waterjet with slower cutting–the drop density is 1:1000 or 1:10,000 of a stream.
The rotor would need to be refilled and have enough power to accelerate the new water, and solidly built enough to overcome vibration/torque. And fast centrifuges are expensive.
A micofuge will only give a water speed of 125 m/s.