To cube watermelon:
Cut watermelon in half lengthwise. Take one half, and starting at one end slice into 3/4 inch thick slices. Discard the end piece and only slice as many slices as you estimate you’ll need for the recipe.
Take each slice and run a sharp sturdy knife between the peel and the melon. Lift out melon and discard peel.
Cut each slice of melon into 3/4 inch cubes, discarding (or eating) the pieces that don’t closely resemble cubes.
Now take each cube and using the tip of a paring knife gently flip out the seeds.
You’ll find it much easier to remove the seeds after the watermelon has been cubed than to remove them before. Always remove the seeds.
Reserve remaining watermelon for other use.
To cube canteloupe and honey dew: Cut melon in half and scoop out seeds and stringy pulp cleanly, leaving a smooth, firm surface.
Cut each half in half again, then cut each quarter in half lengthwise into wedges.
Now, depending upon the size of the melon you may have to cut in half again, lengthwise. Keep in mind that you want 3/4 inch cubes.
Next, run a sharp knife between the peel and the melon. Lift out melon and discard peel.
Cut melon into 3/4 inch cubes. Discard (or eat) the tips of each wedge in order to keep the pieces nearly uniform.