I'd say Foundation was far less influential than Dune on SW, though. You've basically got the general notion of an ancient, once-benevolent Galactic Empire that is now crumbling into chaos; characters named "Bail" and "Han"; and three-dimensional holographic recordings. That's about it.

Having said that, Asimov's "force-blades" from his Lucky Starr juvenile novel series may have been one of the principal influences on the lightsaber. They're basically similar to sabers, except their blades are made of invisible force-fields, and are more the length of a large knife blade. Asimov seems to have imagined the force-blade as ideal for stealthy, brutal attacks, whereas Lucas wanted to create elegant sword-style weapons.

The other major "Asimovian" idea in SW is the presence of sentient robots... but that's not specifically drawn from Foundation, more from Asimov's other short fiction in general. (The Susan Calvin series, etc.)