First chop the tuna and put it into in a bowl with the lime juice
In the same bowl add the chopped onions, cucumber and mango
Then add the sesame oil, if you don’t have sesame oils you can use olive oil
At the end taste it and add the salt and pepper.
How to serve it
The typical way is to serve it in a corn tostada, if you don’t have tostadas you can serve it in crackers