Cut the leek lengthwise in half and rinse thoroughly. Cut lengthwise again into smaller parts, then crosswise into pieces. Place in a sieve and pour boiling water over it from a kettle.
Drain the corn on the same sieve. Transfer the ingredients from the sieve to a larger bowl and add chopped pineapple.
Empty the can of beans onto the sieve and rinse with water. Drain and add to the bowl.
Add diced bell pepper and small-diced yellow cheese. Add mayonnaise, season with salt and pepper, mix. Transfer to a clean salad bowl, garnish with parsley.