Some things the game doesn't simulate very well…
A Handful for an Eye isn't a trope the game handles well. Even Pathfinder's combat maneuver dirty trick by default only works occasionally in melee against one foe and provokes attacks of opportunity (not at a distance versus two foes), and on its turn that one foe can take a move action to end the blindness.
In Dungeons and Dragons 3.5 there are, of course, feats that enable mundane creatures do this—the tactical feat Blinding Strike (Dragon #345 90-1) or the feat Eye Rake (Dragon #304 84), for example—and equipment that enables anyone to do this—Ursuma pepper powder is my favorite, for example, but blinding sand ammunition for the exotic weapon sandpipe (Secrets of Sarlona 136, 137) (50 gp; 0.5 lbs.) can be used without a sandpipe against an adjacent creature, and there's the hideously unbalanced eggshell grenade (dust) (Oriental Adventures 78) (10 gp; 0 lbs.) which will get you kicked in the shins—, but a straight-up method of even momentary blindness isn't an everyday, mundane, I-know-what-should-try! combat option in D&D 3.5.
…But things can be reskinned
Any creature can make a Bluff check to create a diversion to hide:
You can use the Bluff skill to help you hide. A successful Bluff check [opposed by creatures' Sense Motive skill checks] gives you the momentary diversion you need to attempt a Hide check while people are aware of you. This usage does not provoke an attack of opportunity.… A Bluff check made to… create a diversion to hide is a standard action. (PH 68)
Then, if successful, if the PC can reach a hiding spot, the PC can then make a Hide skill check that suffers a −10 penalty that's opposed by the onlookers' Spot skill checks. If the PC's Hide skill check then succeeds against all potential viewers (in this case, two), he's Batmanned out of there. (More about how to use the Bluff and Hide skill this way is covered by this question.)
However, this won't actually get the PC past the guards—that's still a Tumble skill check—, but the PC could make the Tumble skill check in conjunction with his movement to get to a hiding place beyond the guards. Note that this DM would rule that simply getting out of the guards' lines of sight is sufficient, a successful Hide check then indicating the guards don't know which way the PC went (assuming there's a choice).
Keep in mind: This is both a difficult and a highly situational tactic. Considering the circumstances you've described, I expect the game expects the PC to fight the darn guards, having made it so hard for the mundane creature to bypass them. And I also suspect that, were this fight against evenly matched foes, the game expects the PC to lose and either be killed or subdued. That's what happens. Employing pocket sand in a simulationist system shouldn't be a go-to option but an act of desperation that—sadly for the PC—probably won't work.
"But I want to take a standard action to blind multiple foes at a distance with sand from my belt pouch!"
That's magic. Cast glitterdust.
One last thing: Consider narrating if it's appropriate
If the PC is level 10 and the guards are level 1 (or similar extreme power discrepancy), there's very little the guards can do to stop the PC anyway. Allowing the PC to bypass such low-level threats automatically without making any rolls is okay. Just let the player describe how his PC bypasses the stooges—either within the realm of action hero possibility or not, depending on the campaign and the DM. There's no reason to detail every combat: while it's possible for the encounter to become a series of PC 1s and guard 20s, that possibility's so remote that trying for it wastes everybody's time.