Peel the cucumber, slice it into quarters (lengthwise), remove the seeds, and dice into pieces. Prepare the mango by peeling it, cutting off each half lengthwise from the center pit, and dicing the flesh. Slice open the avocado, remove the pit, score the flesh, and scoop out the diced pieces with a spoon. Finally, slice off the top of the jalapeno, slice it in half, remove the seeds, and finely chop it. Combine everything in a large bowl. Add the cilantro and sesame seeds.
In a small bowl, whisk together the olive oil, lime juice, and honey. Pour this over the salad and mix until it's well coated.
This is best when enjoyed right away or within 1-2 days. Store in an airtight container in the fridge before serving.