What Procedure Shortens the Length of Nostrils?

Your nostrils do appear to be somewhat elongated and narrow. What you are being critical of is the nostril length to tip lobule disproportionation that you exhibit. In other words the length of your nostril is too long compared to the length of the tip of your nose that you see on the views that you have provided. Correction of this issue would depend upon what other changes would need to be made to your nose during rhinoplasty. The relative narrow shape to the nostril may be corrected by shortening your nose, if that is what your nose requires, or with the use of alar rim grafts to round out the nostril shape. All of these issues, and the limitations of the procedures, can be discussed with an experienced rhinoplastic surgeon

Your question is best answered by first asking what are the normal or average nostril nasal proportions. The answer to that is the distance between the outer edges of the nostrils should be equivalent to the distance between the inner and outer corners of the eyes for optimal proportions. In most people that is 32mm. The remainder of the nostril proportions should follow the 1/3 to 2/3 rule best described in my blog http://aaronstonemd-plasticsurgery.blogspot.com/2009/02/facial-proportions-analysis-is-cosmetic.html
If the base to tip length (B in the bottom image on the blog) is more than 2/3 of the tip to root length (A in the bottom image on the blog) then adjustments in front to back nostril length are justified. The devil is in the details as there is more than one way to do that based on why the length is more than 2/3. Direct surgery on the tip cartilage, removal of some of the septal cartilage, surgery on the nasal spine or some combination of these would be required to achieve the result you are describing. None of this can be assessed from a single photo at the angle you took the above photo.

There are no procedures for nostril tightening. It is difficult to assess from this particular view, but most "long and narrow" nostrils are cuased by an overly projecting nasal tip. Correction usually involves component reduction of the dorsum and diminished projection of the tip.