Mix together the black sesame seed paste, ponzu, and rayu in the same bowl that you plan to eat the noodles. Set aside.
Cook the noodles according to the directions on the package. Drain and rinse the noodles under running water until the noodles are cool.
Drain and place the noodles in the bowl with the sauce mixture. Toss, toss, toss!
Top with roasted black sesame seeds and thinly sliced shiso leaves. Eat and enjoy.