As with any bicycle, tires will make a difference in how an eBike handles and performs. Remember that eBikes will typically be subject to more torque and weight than acoustic bikes. Tires come in different sizes (diameters), different widths, different pressure levels, and different tread patterns. Each factor can provide different benefits and trade offs to specific biking styles.
Generally speaking, a large diameter tire will offer more speed and efficiency (you will be able to go further and faster with less effort). For inexperienced riders, the larger diameter wheels will feel harder to control or more unstable. Similarly, higher pressure tires will roll faster.
Low pressure/Fat (wide) tires will absorb lots of bumps in the road, and thus offer a very comfortable ride. They are also generally smaller diameter and feel more stable. Low pressure/fat tires do not go very fast, and will consume more battery power to go the same distance.
The tread pattern on the tire will also determine a how the bike feels on the road. Knobby tires work well in loose gravel, but are loud and inefficient on paved surfaces. Smooth tire treads work well on paved roads.
Recommendation: This will somewhat come down to rider preference and where you ride. Short, fat, knobby tires, running off of lower pressure offer a relatively smooth ride for casual riders that ride on dirt roads (and beaches in particular), but they will not be very fast or efficient. Taller, skinnier high-pressure tires will offer far greater speeds and distances if you aren't traveling off road. The sweet spot is in the middle, about 2" wide with smaller knobs/treads. You will want to buy quality tires to avoid punctures and withstand the extra torque and weight found on an eBike.