Take the peas out of the pods, and boil for 4-5 minutes in boiling water (enough to cover the peas completely) with 1/2 teaspoon of salt.
Try one and when it's your desired softness, turn off the heat, and let them cool down in the cooking water. This prevents the peas from getting wrinkled.
Wash the rice and transfer in a sieve. When the Step 2 peas are cooled, transfer into a rice cooker with the rice and 200 ml of pea cooking water. Add water until it reaches the line marked "2" in the inner pot of the rice cooker.
Add the konbu, and 1/2 teaspoon of salt into the rice cooker, and turn on the switch. Leave the remaining peas soaked in the cooking water until the rice is ready.
When the rice is cooked, take out the konbu. Transfer the peas in the sieve to drain the excess water, add to the rice, and mix. Please mix gently so that the peas won't get crushed.
The fluffy bean rice is ready to be served.
I tried with frozen peas, and they were fluffy as you can see in the picture.