Prepare the Tuna: Add the drained canned tuna to a bowl. Add the dashi powder, soy sauce, and rice vinegar, then mix well.
Slice the Cucumber: Thinly slice the cucumber.
Combine: Add the sliced cucumber to the seasoned tuna and toss until evenly coated.
Serve: Taste and adjust the seasoning as needed. Transfer to a serving plate and enjoy!
Notes
Drain the tuna well before mixing to prevent excess liquid.
Enjoy the salad right away for a fresh, crisp cucumber texture. For softer, more seasoned cucumbers, let the salad sit for a short time before serving.
The saltiness of canned tuna and dashi powder can vary, so start with a small amount and add more as needed.