Yes, you can flush the eyes with saline solution that is made for use in eyes.
If the disharge is yellow-green, or the eye apears red, then he may have a bacterial infection and need topical antibiotics to cure it. This would require a trip to the vet clinic.
If he is squinting and sensitive to light, he may have a scratch on his cornea. If this is the case, it is important to get him into the vet as soon as possible to prevent the scratch from becoming infected.
Sometimes a little benadryl can help as well. The dose is 1 mg per pound of body weight evey 8 hour by mouth.
www.VeterinaryPartner.com/Content.plx?P=A&A=554 corneal ulcers in dogs