Maybe, sort of, though it won't cause a horde of demons to spawn, and will surely lose you a dwarf.
Find a spot where rock goes all the way through the magma sea to the semi-molten rock so you have a dry place to work. Dig all the way down to the semi-molten rock, then dig out a channel next to the lowest level of your staircase, though not on the staircase itself. This will leave a "magma flow" floor over the top of a rock ramp where you removed one square of semi-molten rock. Then, construct a floor over the magma flow, then remove it. That should leave a diggable-rock floor where the magma flow once was. Make sure a miner has to stand on that tile to dig it, then channel it out. The miner will drop down onto the former semi-molten rock tile. Now, channel the rock ramp that that miner is standing on. Then, repeat that last step until the miner falls through into hell itself.
While you can't build on tiles with a rock ramp, you can probably construct a staircase through the open space that is left once they are removed. That will allow access to hell once your sacrificial miner has broken through. This method won't give the same sense of accomplishment, however, as you'll only have to deal with occasional single or paired demons wandering in from the map edges, not the group that spawns when you pierce an adamantine tube.