In a large skillet, heat the 2 tablespoons of oil. Add the shallots and cook over moderately high heat until lightly browned, about 2 minutes. Add the wine and cook until reduced by about half, 2 to 3 minutes. Add the oyster sauce and simmer until slightly thickened, about 2 minutes. Add the asparagus and lime juice; toss to coat. Transfer the asparagus and sauce to 4 dinner plates. Top with the crabs and cilantro and serve at once.