In a small bowl, stir together harissa, lemon juice, and garlic. Set aside.
Rinse ribs and pat dry. Use a dull butter knife to loosen thin papery membrane that runs along underside, then pull it off with your fingers. Rub ribs generously on both sides with salt and pepper, then slather all over with harissa rub. Wrap ribs in plastic wrap and marinate, refrigerated, for at least 8 and up to 24 hours.
Set up a charcoal or gas grill for medium indirect heat (300° to 350°; you should be able to hold your hand 1 to 2 in. above the hottest area of grill level only 4 to 5 seconds). Place ribs, bone side down, in cooler part of the grill; close lid. Cook, basting gently with beer on both sides every 10 minutes (keep ribs bone side down), until ribs are tender and cooked through and meat has shrunk back from ends of the bones, 40 to 50 minutes total. Try to keep harissa paste on the ribs while basting. Serve ribs hot, with salad.
Note: Nutritional analysis is per serving.