Cut the onions and saute' until light brown in the olive oil using a large skillet. Meanwhile, chop the garlic and wash the greens. Remove and discard the tough stems from the greens and cut the leaves into 1/2-inch strips. Add the greens and garlic and a splash of water if greens are not still wet from washing. Cover to steam for 2 minutes. Uncover, add tamari, and saute' for 3 minutes. Cool or refrigerate overnight. When ready to serve, toss in the artichoke hearts and sliced hard-boiled eggs.