spectracide has a kill all that I prefer for my lawn and garden areas. Make sure to get a bottle that has a narrow spray pattern. If you want to kill just the foxtail spray them individually, unless they have been left to grow out of control in your lawn. Maintenance is the only thing that will keep your lawn from having these types of issues. You need to get on top of weeks quickly and use the proper solution, or you will end up having to do what you are doing.
You can usually reseed after 2 days with most kill all products. I would till it up at the very least to allow the new grass to take root more easily.

 

Have you tried smoking them?

 

Chemical Control

Two weeks before green foxtail germinates use a pre emergent herbicide that contains one of the following benefin, bensulide, dithiopyr, oryzalin, pendimethalin, or prodiamine. Be sure to water the herbicide into the lawn. If the spring application does not take care of the problem try another application. After Germination your options then are post-emergent product or simply mowing more often to control the seed population. Do rake or sweep up these mowed foxtail areas, otherwise you are simply reseeding your lawn with new seeds. Fertilizing with a good fertilizer to increase your lawn grass density to crowd out the major weeds and works well with the previous option.