This is a great way to remove the seeds from a jalapeño or chile while minimizing contact with the seeds or having the chile squirt at you while trying to scrape the seeds out.
Slice off the tip
To make the chile more stable while you are cutting it, slice off a small amount of the tip.
Slice off flesh
Insert your knife in the top of the chile, blade down and slice the flesh off of the chile in a downward curve.
Continue to slice the flesh off in downward strokes.
Remove all the flesh
Continue slicing until all of the flesh is removed leaving only the seeds and stem behind.
Prepare chile strips
Lay the chile flesh down in a row.
Slice the chile strips lengthwise
Place the skin side down and slice the strips into match-stick sized pieces.
Slice the strips again
Now slice the strips the opposite way to create little cubes.
Your diced chile is now ready
The chile is now ready to be used in your recipe calling for "seeded and diced" jalapeño or chile.