In soil no it wont rinse out "extra" salts. The reason in chemistry.If you over feed your plant it will help to clear the SOIL / MEDIUM and like mentioned. With a container plant if you push a bunch of PH'ed water through the soil. It will help remove salts that have built up. Making way for the transition from Veg to Flower.
There is a trick if you don't want the plant to take up any additional nuit's that are still in the soil / medium. The last 7 to 10 days / 2 weeks before you cut them. Only give them water at a PH higher then 8.5, you cause lock out on purpose. Anything PH'ed below 7 the plant will try and take in, above that it can't.
They still can drink but you restrict the roots from pulling up more nuit's into the plant. The plants will finish with what it has built up inside itself.
Most of the nuit's are derivatives of metals and water will not remove them from the PLANT. An example in humans some have to much iron in their blood. You need to have blood removed and a transfusion to remove it from your body.
Cations have a molecular charge.
Cations are you fertilizers or "salts".
Molecules that have a charge atract to and attach to soil particles.
No amount of water will "rinse" them away.
The reason is:
water has neither a Positive or Negative molecular charge.
So the attached "salt" molecules cannot be "rinsed" / "flushed" or whatever term you want to use for running water thru soil and expecting some Physics miracle to happen.
I mentions Nitrogen "can" be one nutrient you can over use and the excess "can" become more mobile but it depends on the soil make-up.
Thats the slimmed down version.
Flushing is for SOIL-LESS medium or hydroponics.