Place the rice and water in a large sauce pan over medium high heat.
Once the water is bubbling gently, turn the heat down to low and cover with a lid. Simmer for 13 minutes (do not stir or remove the lid).
With the lid still on, remove the saucepan from the stove and allow to stand for 10 minutes, undisturbed. Fluff with a fork.
Add the frozen sweetcorn to the rice to help cool it down quickly. Refrigerate until needed.
Place dressing ingredients in a jar and shake. Taste test and adjust to your preference.
Place cooled rice, tuna and salad ingredients into a large mixing bowl. Drizzle with the dressing, toss and serve.
Video
Notes
Canned tuna weights vary from country to country. This does not have to be exact. Use two cans roughly 140-185g / 4-6oz each.
Slice the cucumber in half lengthwise and dice. No need to peel or seed if using English or Persian cucumbers. For other types of cucumbers, do seed and peel.
Nutritional information is a rough guide only, calculated using an online nutrition calculator.