Cut the stems off the artichokes. Place the stems and artichokes in a steamer basket set over 1 inch of simmering water. Cover and steam over moderate heat until the artichoke bottoms are tender when pierced with a knife, about 40 minutes. When cool enough to handle, pull the leaves off the artichokes and trim off any fibrous outer skin. Using a spoon, scrape out the hairy chokes. Quarter the artichoke bottoms. Peel the artichoke stems and cut them into 1/2-inch rounds.
In a small skillet, toast the cumin seeds over moderate heat until fragrant, about 40 seconds. Transfer to a spice grinder and let cool. Grind the cumin seeds to a powder and transfer to a large, shallow dish. Stir in the olive oil, vinegar and oregano and season with salt and pepper. Add the artichokes and coat well with the cumin marinade. Let stand at room temperature for 1 hour or refrigerate overnight.
In a large heatproof bowl, pour the boiling water over the bulgur. Cover and let stand until the water is absorbed and the bulgur is tender, about 40 minutes. Fluff with a fork. Stir in the olive oil, lemon juice, scallions, parsley, plum tomato and mint; season with salt and pepper. Cover and refrigerate for 1 hour, or until chilled.
In a bowl, toss the cherry tomatoes with the spinach, feta and pine nuts. Spoon 2 tablespoons of the marinade from the artichokes over the salad and toss well; season with salt and pepper.
Spoon the tabbouleh onto plates and surround with the artichokes. Top with the spinach salad and serve.
The recipe can be prepared through Step 3 up to 1 day ahead.