Use a fork (or potato masher) to gently smash the chickpeas, then add all other ingredients and mix well. Taste and adjust seasoning if necessary
For the rice:
Cook the rice according to the instructions on the packet and leave it to cool down until the rice is cool enough to handle easily without burning your hands!
Mix the shiso seasoning into the rice (if using)
Make sure your hands are wet (this is crucial to make sure the rice doesn't stick to your hands) and take ¼ of the rice and shape into a spherical shape in your hands
Make a little well in the middle and add a small amount of the filling into the well and carefully wrap the rice around the filling and shape into a ball/triangular shape using your hands
Repeat with the remaining ingredients. You should be able to make 4 onigiri
Wrap the nori seaweed around the bottom of the onigiri as shown in the photo
Either enjoy immediately or keep in the fridge for up to a couple of days (best eaten cold)
Notes
If you're pressed for time, you could just mix the smashed chickpeas with store-bought mayonnaise (vegan or otherwise). You can use any leftover filling for salads, pasta, sandwiches, wraps etc!