Salamanca said he earned an associate degree at a community college and will attend Drake University. He said he tells Hispanic youths, "don't let your undocumented status prevent you from achieving your goals."
Some House Republicans have expressed interest in a version of the DREAM Act, although King calls it "backdoor amnesty."
The Obama administration and many activist groups have said they will not settle for the DREAM Act alone. They are pressing the GOP-controlled House to embrace something similar to the Senate bill.
Many House Republicans resist the idea. They point to GOP primary voters in their districts who oppose "amnesty" for people here illegally, and who say a Democratic administration can't be trusted to keep promises to tighten the border with Mexico.
Durbin noted that President Barack Obama won re-election with strong backing from Hispanic and Asian-American voters. Many Republican strategists say their party must improve its relationship with these groups, and backing broad immigration changes could help.
"If Republicans in the House don't respond honestly and in a comprehensive way, this will continue to overshadow any other political issue among certain groups of Americans," Durbin said.
Opponents of the Senate bill say they will use the August recess to stiffen House resistance. About 100 individuals and groups, led by the Tea Party Patriots, sent a letter this week to all House members expressing opposition to any legislation "that bears any resemblance to ... the Senate amnesty bill."
Meanwhile the pro-immigration-reform group America's Voice said its activists "are on the move with hundreds of grassroots events planned from coast to coast" this summer.
Demonstrators, who support legalization for millions now here illegally, blocked a major street outside the U.S. Capitol on Thursday, and some were arrested.
Rep. Devin Nunes, R-Calif., said such protesters do their cause more harm than good.
"People just see it as a campaign," Nunes said in an interview Friday. "People get their feet set in cement when they see campaigns going on."
King, meanwhile, said he was mourning the death of a Vietnam War hero on Friday rather than responding to Durbin's and Harkin's visit to his district.
Editor's Note: Associated Press writer Erica Werner in Washington contributed to this report. Babington reported from Washington.