In a small pot, combine the rice, a big pinch of salt, and 3/4 cup of water. Heat to boiling on high. Once boiling, reduce the heat to low. Cover and cook, without stirring, 15 to 17 minutes, or until the water has been absorbed and the rice is tender. Turn off the heat and fluff with a fork; stir in the mirin.

Meanwhile, wash and dry the fresh produce. Halve and pit the avocado. Using a spoon, remove the avocado from the skin, then thinly slice. Place in a bowl; season with salt and pepper. Halve the radishes lengthwise, then thinly slice crosswise. Halve the cucumbers lengthwise, then thinly slice crosswise. In a bowl, combine the sliced radishes, sliced cucumbers, sesame oil, and vinegar. Season with salt and pepper. Set aside to marinate, stirring occasionally, at least 10 minutes. In a separate bowl, combine the mayonnaise and as much of the yuzu kosho as you'd like, depending on how spicy you'd like the dish to be.  

Pat half the shrimp (you will have extra) dry with paper towels; remove the tails if desired. Season with salt and pepper. In a medium pan (nonstick, if you have one), heat a drizzle of olive oil on medium-high until hot. Add the seasoned shrimp. Cook, stirring occasionally, 4 to 5 minutes, or until opaque and cooked through. Turn off the heat. Serve the cooked rice topped with the cooked shrimp, marinated vegetables (including any liquid), and seasoned avocado. Drizzle with the yuzu mayo. Garnish with the sesame seeds. Enjoy!