Heat the olive oil in a medium sauce-pan. Add the shallots and jalapeño and cook over low heat until softened, about 5 minutes. Add the rice and thyme and stir to coat the rice with the flavorings. Pour in the ham stock and bring to a boil. Reduce the heat to low and simmer, stirring occasionally, until the rice is just tender and the stew is somewhat soupy, about 15 minutes. Add the peas, crabmeat, scallion, lemon juice and the reserved ham and simmer for 1 minute to heat through. Season with salt and pepper and serve at once.