Push to run motorized appliance switch
There are certainly switches available, like this Leviton:

or if you don't like Decora style, here is another one suggested by @Alaska Man also from Leviton:

The key phrase is momentary contact. Make sure you get something properly designed for 120V use. There are tons of switches from Digikey and similar places for use in building electronic stuff. But for a disposal you need something UL-listed (or equivalent).
Make sure the switch can handle the disposal. Lights are easy on a switch (especially with today's low-power LEDs). Motors like disposals are not. These two examples are rated for up 1/2 HP @ 120V, which is enough for a standard (in my area) Badger 5 but not for some bigger models.