Kwame Onwuachi is creating a new concept in Washington, D.C. called Dōgon with an Afro-Caribbean focus. | Photo courtesy of Dōgon.Perhaps one of the most anticipated restaurant openings this spring will be Kwame Onwuachi’s return to Washington, D.C.The chef, whose New York City restaurant Tatiana was named among the nation’s best new restaurants last year,…